# 1.0.0[−][src]Trait std::iter::Iterator

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    #[must_use = "iterators are lazy and do nothing unless consumed"]pub trait Iterator {
        type Item;
    #[lang = "next"]    pub fn next(&mut self) -> Option<Self::Item>;

        pub fn size_hint(&self) -> (usize, Option<usize>) { ... }
        pub fn count(self) -> usize { ... }
        pub fn last(self) -> Option<Self::Item> { ... }
        pub fn advance_by(&mut self, n: usize) -> Result<(), usize> { ... }
        pub fn nth(&mut self, n: usize) -> Option<Self::Item> { ... }
        pub fn step_by(self, step: usize) -> StepBy<Self>ⓘNotable traits for StepBy<I>impl<I> Iterator for StepBy<I> where
        I: Iterator,     type Item = <I as Iterator>::Item; { ... }
        pub fn chain<U>(
            self,
            other: U
        ) -> Chain<Self, <U as IntoIterator>::IntoIter>ⓘNotable traits for Chain<A, B>impl<A, B> Iterator for Chain<A, B> where
        A: Iterator,
        B: Iterator<Item = <A as Iterator>::Item>,     type Item = <A as Iterator>::Item;
        where
            U: IntoIterator<Item = Self::Item>,
        { ... }
        pub fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter>ⓘNotable traits for Zip<A, B>impl<A, B> Iterator for Zip<A, B> where
        A: Iterator,
        B: Iterator,     type Item = (<A as Iterator>::Item, <B as Iterator>::Item);
        where
            U: IntoIterator,
        { ... }
        pub fn map<B, F>(self, f: F) -> Map<Self, F>ⓘNotable traits for Map<I, F>impl<B, I, F> Iterator for Map<I, F> where
        F: FnMut(<I as Iterator>::Item) -> B,
        I: Iterator,     type Item = B;
        where
            F: FnMut(Self::Item) -> B,
        { ... }
        pub fn for_each<F>(self, f: F)
        where
            F: FnMut(Self::Item),
        { ... }
        pub fn filter<P>(self, predicate: P) -> Filter<Self, P>ⓘNotable traits for Filter<I, P>impl<I, P> Iterator for Filter<I, P> where
        I: Iterator,
        P: FnMut(&<I as Iterator>::Item) -> bool,     type Item = <I as Iterator>::Item;
        where
            P: FnMut(&Self::Item) -> bool,
        { ... }
        pub fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>ⓘNotable traits for FilterMap<I, F>impl<B, I, F> Iterator for FilterMap<I, F> where
        F: FnMut(<I as Iterator>::Item) -> Option<B>,
        I: Iterator,     type Item = B;
        where
            F: FnMut(Self::Item) -> Option<B>,
        { ... }
        pub fn enumerate(self) -> Enumerate<Self>ⓘNotable traits for Enumerate<I>impl<I> Iterator for Enumerate<I> where
        I: Iterator,     type Item = (usize, <I as Iterator>::Item); { ... }
        pub fn peekable(self) -> Peekable<Self>ⓘNotable traits for Peekable<I>impl<I> Iterator for Peekable<I> where
        I: Iterator,     type Item = <I as Iterator>::Item; { ... }
        pub fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>ⓘNotable traits for SkipWhile<I, P>impl<I, P> Iterator for SkipWhile<I, P> where
        I: Iterator,
        P: FnMut(&<I as Iterator>::Item) -> bool,     type Item = <I as Iterator>::Item;
        where
            P: FnMut(&Self::Item) -> bool,
        { ... }
        pub fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>ⓘNotable traits for TakeWhile<I, P>impl<I, P> Iterator for TakeWhile<I, P> where
        I: Iterator,
        P: FnMut(&<I as Iterator>::Item) -> bool,     type Item = <I as Iterator>::Item;
        where
            P: FnMut(&Self::Item) -> bool,
        { ... }
        pub fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>ⓘNotable traits for MapWhile<I, P>impl<B, I, P> Iterator for MapWhile<I, P> where
        I: Iterator,
        P: FnMut(<I as Iterator>::Item) -> Option<B>,     type Item = B;
        where
            P: FnMut(Self::Item) -> Option<B>,
        { ... }
        pub fn skip(self, n: usize) -> Skip<Self>ⓘNotable traits for Skip<I>impl<I> Iterator for Skip<I> where
        I: Iterator,     type Item = <I as Iterator>::Item; { ... }
        pub fn take(self, n: usize) -> Take<Self>ⓘNotable traits for Take<I>impl<I> Iterator for Take<I> where
        I: Iterator,     type Item = <I as Iterator>::Item; { ... }
        pub fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>ⓘNotable traits for Scan<I, St, F>impl<B, I, St, F> Iterator for Scan<I, St, F> where
        F: FnMut(&mut St, <I as Iterator>::Item) -> Option<B>,
        I: Iterator,     type Item = B;
        where
            F: FnMut(&mut St, Self::Item) -> Option<B>,
        { ... }
        pub fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>ⓘNotable traits for FlatMap<I, U, F>impl<I, U, F> Iterator for FlatMap<I, U, F> where
        F: FnMut(<I as Iterator>::Item) -> U,
        I: Iterator,
        U: IntoIterator,     type Item = <U as IntoIterator>::Item;
        where
            F: FnMut(Self::Item) -> U,
            U: IntoIterator,
        { ... }
        pub fn flatten(self) -> Flatten<Self>ⓘNotable traits for Flatten<I>impl<I, U> Iterator for Flatten<I> where
        I: Iterator,
        U: Iterator,
        <I as Iterator>::Item: IntoIterator,
        <<I as Iterator>::Item as IntoIterator>::IntoIter == U,
        <<I as Iterator>::Item as IntoIterator>::Item == <U as Iterator>::Item,     type Item = <U as Iterator>::Item;
        where
            Self::Item: IntoIterator,
        { ... }
        pub fn fuse(self) -> Fuse<Self>ⓘNotable traits for Fuse<I>impl<I> Iterator for Fuse<I> where
        I: Iterator,     type Item = <I as Iterator>::Item; { ... }
        pub fn inspect<F>(self, f: F) -> Inspect<Self, F>ⓘNotable traits for Inspect<I, F>impl<I, F> Iterator for Inspect<I, F> where
        F: FnMut(&<I as Iterator>::Item),
        I: Iterator,     type Item = <I as Iterator>::Item;
        where
            F: FnMut(&Self::Item),
        { ... }
        pub fn by_ref(&mut self) -> &mut SelfⓘNotable traits for &'_ mut Fimpl<'_, F> Future for &'_ mut F where
        F: Unpin + Future + ?Sized,     type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
        I: Iterator + ?Sized,     type Item = <I as Iterator>::Item;impl<R: Read + ?Sized, '_> Read for &'_ mut Rimpl<W: Write + ?Sized, '_> Write for &'_ mut W { ... }
    #[must_use =
      "if you really need to exhaust the iterator, consider `.for_each(drop)` instead"]    pub fn collect<B>(self) -> B
        where
            B: FromIterator<Self::Item>,
        { ... }
        pub fn partition<B, F>(self, f: F) -> (B, B)
        where
            B: Default + Extend<Self::Item>,
            F: FnMut(&Self::Item) -> bool,
        { ... }
        pub fn partition_in_place<'a, T, P>(self, predicate: P) -> usize
        where
            P: FnMut(&T) -> bool,
            Self: DoubleEndedIterator<Item = &'a mut T>,
            T: 'a,
        { ... }
        pub fn is_partitioned<P>(self, predicate: P) -> bool
        where
            P: FnMut(Self::Item) -> bool,
        { ... }
        pub fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R
        where
            F: FnMut(B, Self::Item) -> R,
            R: Try<Ok = B>,
        { ... }
        pub fn try_for_each<F, R>(&mut self, f: F) -> R
        where
            F: FnMut(Self::Item) -> R,
            R: Try<Ok = ()>,
        { ... }
        pub fn fold<B, F>(self, init: B, f: F) -> B
        where
            F: FnMut(B, Self::Item) -> B,
        { ... }
        pub fn fold_first<F>(self, f: F) -> Option<Self::Item>
        where
            F: FnMut(Self::Item, Self::Item) -> Self::Item,
        { ... }
        pub fn all<F>(&mut self, f: F) -> bool
        where
            F: FnMut(Self::Item) -> bool,
        { ... }
        pub fn any<F>(&mut self, f: F) -> bool
        where
            F: FnMut(Self::Item) -> bool,
        { ... }
        pub fn find<P>(&mut self, predicate: P) -> Option<Self::Item>
        where
            P: FnMut(&Self::Item) -> bool,
        { ... }
        pub fn find_map<B, F>(&mut self, f: F) -> Option<B>
        where
            F: FnMut(Self::Item) -> Option<B>,
        { ... }
        pub fn try_find<F, R>(
            &mut self,
            f: F
        ) -> Result<Option<Self::Item>, <R as Try>::Error>
        where
            F: FnMut(&Self::Item) -> R,
            R: Try<Ok = bool>,
        { ... }
        pub fn position<P>(&mut self, predicate: P) -> Option<usize>
        where
            P: FnMut(Self::Item) -> bool,
        { ... }
        pub fn rposition<P>(&mut self, predicate: P) -> Option<usize>
        where
            P: FnMut(Self::Item) -> bool,
            Self: ExactSizeIterator + DoubleEndedIterator,
        { ... }
        pub fn max(self) -> Option<Self::Item>
        where
            Self::Item: Ord,
        { ... }
        pub fn min(self) -> Option<Self::Item>
        where
            Self::Item: Ord,
        { ... }
        pub fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>
        where
            B: Ord,
            F: FnMut(&Self::Item) -> B,
        { ... }
        pub fn max_by<F>(self, compare: F) -> Option<Self::Item>
        where
            F: FnMut(&Self::Item, &Self::Item) -> Ordering,
        { ... }
        pub fn min_by_key<B, F>(self, f: F) -> Option<Self::Item>
        where
            B: Ord,
            F: FnMut(&Self::Item) -> B,
        { ... }
        pub fn min_by<F>(self, compare: F) -> Option<Self::Item>
        where
            F: FnMut(&Self::Item, &Self::Item) -> Ordering,
        { ... }
        pub fn rev(self) -> Rev<Self>ⓘNotable traits for Rev<I>impl<I> Iterator for Rev<I> where
        I: DoubleEndedIterator,     type Item = <I as Iterator>::Item;
        where
            Self: DoubleEndedIterator,
        { ... }
        pub fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)
        where
            FromA: Default + Extend<A>,
            FromB: Default + Extend<B>,
            Self: Iterator<Item = (A, B)>,
        { ... }
        pub fn copied<'a, T>(self) -> Copied<Self>ⓘNotable traits for Copied<I>impl<'a, I, T> Iterator for Copied<I> where
        I: Iterator<Item = &'a T>,
        T: 'a + Copy,     type Item = T;
        where
            Self: Iterator<Item = &'a T>,
            T: 'a + Copy,
        { ... }
        pub fn cloned<'a, T>(self) -> Cloned<Self>ⓘNotable traits for Cloned<I>impl<'a, I, T> Iterator for Cloned<I> where
        I: Iterator<Item = &'a T>,
        T: 'a + Clone,     type Item = T;
        where
            Self: Iterator<Item = &'a T>,
            T: 'a + Clone,
        { ... }
        pub fn cycle(self) -> Cycle<Self>ⓘNotable traits for Cycle<I>impl<I> Iterator for Cycle<I> where
        I: Clone + Iterator,     type Item = <I as Iterator>::Item;
        where
            Self: Clone,
        { ... }
        pub fn sum<S>(self) -> S
        where
            S: Sum<Self::Item>,
        { ... }
        pub fn product<P>(self) -> P
        where
            P: Product<Self::Item>,
        { ... }
        pub fn cmp<I>(self, other: I) -> Ordering
        where
            I: IntoIterator<Item = Self::Item>,
            Self::Item: Ord,
        { ... }
        pub fn cmp_by<I, F>(self, other: I, cmp: F) -> Ordering
        where
            F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,
            I: IntoIterator,
        { ... }
        pub fn partial_cmp<I>(self, other: I) -> Option<Ordering>
        where
            I: IntoIterator,
            Self::Item: PartialOrd<<I as IntoIterator>::Item>,
        { ... }
        pub fn partial_cmp_by<I, F>(
            self,
            other: I,
            partial_cmp: F
        ) -> Option<Ordering>
        where
            F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,
            I: IntoIterator,
        { ... }
        pub fn eq<I>(self, other: I) -> bool
        where
            I: IntoIterator,
            Self::Item: PartialEq<<I as IntoIterator>::Item>,
        { ... }
        pub fn eq_by<I, F>(self, other: I, eq: F) -> bool
        where
            F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,
            I: IntoIterator,
        { ... }
        pub fn ne<I>(self, other: I) -> bool
        where
            I: IntoIterator,
            Self::Item: PartialEq<<I as IntoIterator>::Item>,
        { ... }
        pub fn lt<I>(self, other: I) -> bool
        where
            I: IntoIterator,
            Self::Item: PartialOrd<<I as IntoIterator>::Item>,
        { ... }
        pub fn le<I>(self, other: I) -> bool
        where
            I: IntoIterator,
            Self::Item: PartialOrd<<I as IntoIterator>::Item>,
        { ... }
        pub fn gt<I>(self, other: I) -> bool
        where
            I: IntoIterator,
            Self::Item: PartialOrd<<I as IntoIterator>::Item>,
        { ... }
        pub fn ge<I>(self, other: I) -> bool
        where
            I: IntoIterator,
            Self::Item: PartialOrd<<I as IntoIterator>::Item>,
        { ... }
        pub fn is_sorted(self) -> bool
        where
            Self::Item: PartialOrd<Self::Item>,
        { ... }
        pub fn is_sorted_by<F>(self, compare: F) -> bool
        where
            F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,
        { ... }
        pub fn is_sorted_by_key<F, K>(self, f: F) -> bool
        where
            F: FnMut(Self::Item) -> K,
            K: PartialOrd<K>,
        { ... }
    }

An interface for dealing with iterators.

This is the main iterator trait. For more about the concept of iterators generally, please see the module-level documentation. In particular, you may want to know how to implement `Iterator`.

## Associated Types

### `type Item`[src]

The type of the elements being iterated over.

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## Required methods

### `#[lang = "next"]pub fn next(&mut self) -> Option<Self::Item>`[src]

Advances the iterator and returns the next value.

Returns `None` when iteration is finished. Individual iterator implementations may choose to resume iteration, and so calling `next()` again may or may not eventually start returning `Some(Item)` again at some point.

# Examples

Basic usage:

    let a = [1, 2, 3];

    let mut iter = a.iter();

    // A call to next() returns the next value...
    assert_eq!(Some(&1), iter.next());
    assert_eq!(Some(&2), iter.next());
    assert_eq!(Some(&3), iter.next());

    // ... and then None once it's over.
    assert_eq!(None, iter.next());

    // More calls may or may not return `None`. Here, they always will.
    assert_eq!(None, iter.next());
    assert_eq!(None, iter.next());

Run
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## Provided methods

### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

Returns the bounds on the remaining length of the iterator.

Specifically, `size_hint()` returns a tuple where the first element is the lower bound, and the second element is the upper bound.

The second half of the tuple that is returned is an `Option``<``usize``>`. A `None` here means that either there is no known upper bound, or the upper bound is larger than `usize`.

# Implementation notes

It is not enforced that an iterator implementation yields the declared number of elements. A buggy iterator may yield less than the lower bound or more than the upper bound of elements.

`size_hint()` is primarily intended to be used for optimizations such as reserving space for the elements of the iterator, but must not be trusted to e.g., omit bounds checks in unsafe code. An incorrect implementation of `size_hint()` should not lead to memory safety violations.

That said, the implementation should provide a correct estimation, because otherwise it would be a violation of the trait's protocol.

The default implementation returns `(0,` `None``)` which is correct for any iterator.

# Examples

Basic usage:

    let a = [1, 2, 3];
    let iter = a.iter();

    assert_eq!((3, Some(3)), iter.size_hint());

Run

A more complex example:

    // The even numbers from zero to ten.
    let iter = (0..10).filter(|x| x % 2 == 0);

    // We might iterate from zero to ten times. Knowing that it's five
    // exactly wouldn't be possible without executing filter().
    assert_eq!((0, Some(10)), iter.size_hint());

    // Let's add five more numbers with chain()
    let iter = (0..10).filter(|x| x % 2 == 0).chain(15..20);

    // now both bounds are increased by five
    assert_eq!((5, Some(15)), iter.size_hint());

Run

Returning `None` for an upper bound:

    // an infinite iterator has no upper bound
    // and the maximum possible lower bound
    let iter = 0..;

    assert_eq!((usize::MAX, None), iter.size_hint());

Run

### `pub fn count(self) -> usize`[src]

Consumes the iterator, counting the number of iterations and returning it.

This method will call `next` repeatedly until `None` is encountered, returning the number of times it saw `Some`. Note that `next` has to be called at least once even if the iterator does not have any elements.

# Overflow Behavior

The method does no guarding against overflows, so counting elements of an iterator with more than `usize::MAX` elements either produces the wrong result or panics. If debug assertions are enabled, a panic is guaranteed.

# Panics

This function might panic if the iterator has more than `usize::MAX` elements.

# Examples

Basic usage:

    let a = [1, 2, 3];
    assert_eq!(a.iter().count(), 3);

    let a = [1, 2, 3, 4, 5];
    assert_eq!(a.iter().count(), 5);

Run

### `pub fn last(self) -> Option<Self::Item>`[src]

Consumes the iterator, returning the last element.

This method will evaluate the iterator until it returns `None`. While doing so, it keeps track of the current element. After `None` is returned, `last()` will then return the last element it saw.

# Examples

Basic usage:

    let a = [1, 2, 3];
    assert_eq!(a.iter().last(), Some(&3));

    let a = [1, 2, 3, 4, 5];
    assert_eq!(a.iter().last(), Some(&5));

Run

### `pub fn advance_by(&mut self, n: usize) -> Result<(), usize>`[src]

🔬 This is a nightly-only experimental API. (`iter_advance_by` #77404)

recently added

Advances the iterator by `n` elements.

This method will eagerly skip `n` elements by calling `next` up to `n` times until `None` is encountered.

`advance_by(n)` will return `Ok(())` if the iterator successfully advances by `n` elements, or `Err(k)` if `None` is encountered, where `k` is the number of elements the iterator is advanced by before running out of elements (i.e. the length of the iterator). Note that `k` is always less than `n`.

Calling `advance_by(0)` does not consume any elements and always returns `Ok(())`.

# Examples

Basic usage:

    #![feature(iter_advance_by)]

    let a = [1, 2, 3, 4];
    let mut iter = a.iter();

    assert_eq!(iter.advance_by(2), Ok(()));
    assert_eq!(iter.next(), Some(&3));
    assert_eq!(iter.advance_by(0), Ok(()));
    assert_eq!(iter.advance_by(100), Err(1)); // only `&4` was skipped

Run

### `pub fn nth(&mut self, n: usize) -> Option<Self::Item>`[src]

Returns the `n`th element of the iterator.

Like most indexing operations, the count starts from zero, so `nth(0)` returns the first value, `nth(1)` the second, and so on.

Note that all preceding elements, as well as the returned element, will be consumed from the iterator. That means that the preceding elements will be discarded, and also that calling `nth(0)` multiple times on the same iterator will return different elements.

`nth()` will return `None` if `n` is greater than or equal to the length of the iterator.

# Examples

Basic usage:

    let a = [1, 2, 3];
    assert_eq!(a.iter().nth(1), Some(&2));

Run

Calling `nth()` multiple times doesn't rewind the iterator:

    let a = [1, 2, 3];

    let mut iter = a.iter();

    assert_eq!(iter.nth(1), Some(&2));
    assert_eq!(iter.nth(1), None);

Run

Returning `None` if there are less than `n + 1` elements:

    let a = [1, 2, 3];
    assert_eq!(a.iter().nth(10), None);

Run

### `pub fn step_by(self, step: usize) -> StepBy<Self>ⓘ

### Notable traits for StepBy<I>

`impl<I> Iterator for StepBy<I> where
I: Iterator, type Item = <I as Iterator>::Item;`
`1.28.0[src]

Creates an iterator starting at the same point, but stepping by the given amount at each iteration.

Note 1: The first element of the iterator will always be returned, regardless of the step given.

Note 2: The time at which ignored elements are pulled is not fixed. `StepBy` behaves like the sequence `next(), nth(step-1), nth(step-1), …`, but is also free to behave like the sequence `advance_n_and_return_first(step), advance_n_and_return_first(step), …` Which way is used may change for some iterators for performance reasons. The second way will advance the iterator earlier and may consume more items.

`advance_n_and_return_first` is the equivalent of:

    fn advance_n_and_return_first<I>(iter: &mut I, total_step: usize) -> Option<I::Item>
    where
        I: Iterator,
    {
        let next = iter.next();
        if total_step > 1 {
            iter.nth(total_step-2);
        }
        next
    }

Run

# Panics

The method will panic if the given step is `0`.

# Examples

Basic usage:

    let a = [0, 1, 2, 3, 4, 5];
    let mut iter = a.iter().step_by(2);

    assert_eq!(iter.next(), Some(&0));
    assert_eq!(iter.next(), Some(&2));
    assert_eq!(iter.next(), Some(&4));
    assert_eq!(iter.next(), None);

Run

### `pub fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter>ⓘ

### Notable traits for Chain<A, B>

`impl<A, B> Iterator for Chain<A, B> where
A: Iterator,
B: Iterator<Item = <A as Iterator>::Item>, type Item = <A as Iterator>::Item;`
where
U: IntoIterator<Item = Self::Item>,` [src]

Takes two iterators and creates a new iterator over both in sequence.

`chain()` will return a new iterator which will first iterate over values from the first iterator and then over values from the second iterator.

In other words, it links two iterators together, in a chain. 🔗

`once` is commonly used to adapt a single value into a chain of other kinds of iteration.

# Examples

Basic usage:

    let a1 = [1, 2, 3];
    let a2 = [4, 5, 6];

    let mut iter = a1.iter().chain(a2.iter());

    assert_eq!(iter.next(), Some(&1));
    assert_eq!(iter.next(), Some(&2));
    assert_eq!(iter.next(), Some(&3));
    assert_eq!(iter.next(), Some(&4));
    assert_eq!(iter.next(), Some(&5));
    assert_eq!(iter.next(), Some(&6));
    assert_eq!(iter.next(), None);

Run

Since the argument to `chain()` uses `IntoIterator`, we can pass anything that can be converted into an `Iterator`, not just an `Iterator` itself. For example, slices (`&[T]`) implement `IntoIterator`, and so can be passed to `chain()` directly:

    let s1 = &[1, 2, 3];
    let s2 = &[4, 5, 6];

    let mut iter = s1.iter().chain(s2);

    assert_eq!(iter.next(), Some(&1));
    assert_eq!(iter.next(), Some(&2));
    assert_eq!(iter.next(), Some(&3));
    assert_eq!(iter.next(), Some(&4));
    assert_eq!(iter.next(), Some(&5));
    assert_eq!(iter.next(), Some(&6));
    assert_eq!(iter.next(), None);

Run

If you work with Windows API, you may wish to convert `OsStr` to `Vec<u16>`:

    #[cfg(windows)]
    fn os_str_to_utf16(s: &std::ffi::OsStr) -> Vec<u16> {
        use std::os::windows::ffi::OsStrExt;
        s.encode_wide().chain(std::iter::once(0)).collect()
    }

Run

### `pub fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter>ⓘ

### Notable traits for Zip<A, B>

`impl<A, B> Iterator for Zip<A, B> where
A: Iterator,
B: Iterator, type Item = (<A as Iterator>::Item, <B as Iterator>::Item);`
where
U: IntoIterator,` [src]

'Zips up' two iterators into a single iterator of pairs.

`zip()` returns a new iterator that will iterate over two other iterators, returning a tuple where the first element comes from the first iterator, and the second element comes from the second iterator.

In other words, it zips two iterators together, into a single one.

If either iterator returns `None`, `next` from the zipped iterator will return `None`. If the first iterator returns `None`, `zip` will short-circuit and `next` will not be called on the second iterator.

# Examples

Basic usage:

    let a1 = [1, 2, 3];
    let a2 = [4, 5, 6];

    let mut iter = a1.iter().zip(a2.iter());

    assert_eq!(iter.next(), Some((&1, &4)));
    assert_eq!(iter.next(), Some((&2, &5)));
    assert_eq!(iter.next(), Some((&3, &6)));
    assert_eq!(iter.next(), None);

Run

Since the argument to `zip()` uses `IntoIterator`, we can pass anything that can be converted into an `Iterator`, not just an `Iterator` itself. For example, slices (`&[T]`) implement `IntoIterator`, and so can be passed to `zip()` directly:

    let s1 = &[1, 2, 3];
    let s2 = &[4, 5, 6];

    let mut iter = s1.iter().zip(s2);

    assert_eq!(iter.next(), Some((&1, &4)));
    assert_eq!(iter.next(), Some((&2, &5)));
    assert_eq!(iter.next(), Some((&3, &6)));
    assert_eq!(iter.next(), None);

Run

`zip()` is often used to zip an infinite iterator to a finite one. This works because the finite iterator will eventually return `None`, ending the zipper. Zipping with `(0..)` can look a lot like `enumerate`:

    let enumerate: Vec<_> = "foo".chars().enumerate().collect();

    let zipper: Vec<_> = (0..).zip("foo".chars()).collect();

    assert_eq!((0, 'f'), enumerate[0]);
    assert_eq!((0, 'f'), zipper[0]);

    assert_eq!((1, 'o'), enumerate[1]);
    assert_eq!((1, 'o'), zipper[1]);

    assert_eq!((2, 'o'), enumerate[2]);
    assert_eq!((2, 'o'), zipper[2]);

Run

### `pub fn map<B, F>(self, f: F) -> Map<Self, F>ⓘ

### Notable traits for Map<I, F>

`impl<B, I, F> Iterator for Map<I, F> where
F: FnMut(<I as Iterator>::Item) -> B,
I: Iterator, type Item = B;`
where
F: FnMut(Self::Item) -> B,` [src]

Takes a closure and creates an iterator which calls that closure on each element.

`map()` transforms one iterator into another, by means of its argument: something that implements `FnMut`. It produces a new iterator which calls this closure on each element of the original iterator.

If you are good at thinking in types, you can think of `map()` like this: If you have an iterator that gives you elements of some type `A`, and you want an iterator of some other type `B`, you can use `map()`, passing a closure that takes an `A` and returns a `B`.

`map()` is conceptually similar to a `for` loop. However, as `map()` is lazy, it is best used when you're already working with other iterators. If you're doing some sort of looping for a side effect, it's considered more idiomatic to use `for` than `map()`.

# Examples

Basic usage:

    let a = [1, 2, 3];

    let mut iter = a.iter().map(|x| 2 * x);

    assert_eq!(iter.next(), Some(2));
    assert_eq!(iter.next(), Some(4));
    assert_eq!(iter.next(), Some(6));
    assert_eq!(iter.next(), None);

Run

If you're doing some sort of side effect, prefer `for` to `map()`:

    // don't do this:
    (0..5).map(|x| println!("{}", x));

    // it won't even execute, as it is lazy. Rust will warn you about this.

    // Instead, use for:
    for x in 0..5 {
        println!("{}", x);
    }

Run

### `pub fn for_each<F>(self, f: F) where
F: FnMut(Self::Item),` 1.21.0[src]

Calls a closure on each element of an iterator.

This is equivalent to using a `for` loop on the iterator, although `break` and `continue` are not possible from a closure. It's generally more idiomatic to use a `for` loop, but `for_each` may be more legible when processing items at the end of longer iterator chains. In some cases `for_each` may also be faster than a loop, because it will use internal iteration on adaptors like `Chain`.

# Examples

Basic usage:

    use std::sync::mpsc::channel;

    let (tx, rx) = channel();
    (0..5).map(|x| x * 2 + 1)
          .for_each(move |x| tx.send(x).unwrap());

    let v: Vec<_> =  rx.iter().collect();
    assert_eq!(v, vec![1, 3, 5, 7, 9]);

Run

For such a small example, a `for` loop may be cleaner, but `for_each` might be preferable to keep a functional style with longer iterators:

    (0..5).flat_map(|x| x * 100 .. x * 110)
          .enumerate()
          .filter(|&(i, x)| (i + x) % 3 == 0)
          .for_each(|(i, x)| println!("{}:{}", i, x));

Run

### `pub fn filter<P>(self, predicate: P) -> Filter<Self, P>ⓘ

### Notable traits for Filter<I, P>

`impl<I, P> Iterator for Filter<I, P> where
I: Iterator,
P: FnMut(&<I as Iterator>::Item) -> bool, type Item = <I as Iterator>::Item;`
where
P: FnMut(&Self::Item) -> bool,` [src]

Creates an iterator which uses a closure to determine if an element should be yielded.

Given an element the closure must return `true` or `false`. The returned iterator will yield only the elements for which the closure returns true.

# Examples

Basic usage:

    let a = [0i32, 1, 2];

    let mut iter = a.iter().filter(|x| x.is_positive());

    assert_eq!(iter.next(), Some(&1));
    assert_eq!(iter.next(), Some(&2));
    assert_eq!(iter.next(), None);

Run

Because the closure passed to `filter()` takes a reference, and many iterators iterate over references, this leads to a possibly confusing situation, where the type of the closure is a double reference:

    let a = [0, 1, 2];

    let mut iter = a.iter().filter(|x| **x > 1); // need two *s!

    assert_eq!(iter.next(), Some(&2));
    assert_eq!(iter.next(), None);

Run

It's common to instead use destructuring on the argument to strip away one:

    let a = [0, 1, 2];

    let mut iter = a.iter().filter(|&x| *x > 1); // both & and *

    assert_eq!(iter.next(), Some(&2));
    assert_eq!(iter.next(), None);

Run

or both:

    let a = [0, 1, 2];

    let mut iter = a.iter().filter(|&&x| x > 1); // two &s

    assert_eq!(iter.next(), Some(&2));
    assert_eq!(iter.next(), None);

Run

of these layers.

Note that `iter.filter(f).next()` is equivalent to `iter.find(f)`.

### `pub fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>ⓘ

### Notable traits for FilterMap<I, F>

`impl<B, I, F> Iterator for FilterMap<I, F> where
F: FnMut(<I as Iterator>::Item) -> Option<B>,
I: Iterator, type Item = B;`
where
F: FnMut(Self::Item) -> Option<B>,` [src]

Creates an iterator that both filters and maps.

The returned iterator yields only the `value`s for which the supplied closure returns `Some(value)`.

`filter_map` can be used to make chains of `filter` and `map` more concise. The example below shows how a `map().filter().map()` can be shortened to a single call to `filter_map`.

# Examples

Basic usage:

    let a = ["1", "two", "NaN", "four", "5"];

    let mut iter = a.iter().filter_map(|s| s.parse().ok());

    assert_eq!(iter.next(), Some(1));
    assert_eq!(iter.next(), Some(5));
    assert_eq!(iter.next(), None);

Run

Here's the same example, but with `filter` and `map`:

    let a = ["1", "two", "NaN", "four", "5"];
    let mut iter = a.iter().map(|s| s.parse()).filter(|s| s.is_ok()).map(|s| s.unwrap());
    assert_eq!(iter.next(), Some(1));
    assert_eq!(iter.next(), Some(5));
    assert_eq!(iter.next(), None);

Run

### `pub fn enumerate(self) -> Enumerate<Self>ⓘ

### Notable traits for Enumerate<I>

`impl<I> Iterator for Enumerate<I> where
I: Iterator, type Item = (usize, <I as Iterator>::Item);`
`[src]

Creates an iterator which gives the current iteration count as well as the next value.

The iterator returned yields pairs `(i, val)`, where `i` is the current index of iteration and `val` is the value returned by the iterator.

`enumerate()` keeps its count as a `usize`. If you want to count by a different sized integer, the `zip` function provides similar functionality.

# Overflow Behavior

The method does no guarding against overflows, so enumerating more than `usize::MAX` elements either produces the wrong result or panics. If debug assertions are enabled, a panic is guaranteed.

# Panics

The returned iterator might panic if the to-be-returned index would overflow a `usize`.

# Examples

    let a = ['a', 'b', 'c'];

    let mut iter = a.iter().enumerate();

    assert_eq!(iter.next(), Some((0, &'a')));
    assert_eq!(iter.next(), Some((1, &'b')));
    assert_eq!(iter.next(), Some((2, &'c')));
    assert_eq!(iter.next(), None);

Run

### `pub fn peekable(self) -> Peekable<Self>ⓘ

### Notable traits for Peekable<I>

`impl<I> Iterator for Peekable<I> where
I: Iterator, type Item = <I as Iterator>::Item;`
`[src]

Creates an iterator which can use `peek` to look at the next element of the iterator without consuming it.

Adds a `peek` method to an iterator. See its documentation for more information.

Note that the underlying iterator is still advanced when `peek` is called for the first time: In order to retrieve the next element, `next` is called on the underlying iterator, hence any side effects (i.e. anything other than fetching the next value) of the `next` method will occur.

# Examples

Basic usage:

    let xs = [1, 2, 3];

    let mut iter = xs.iter().peekable();

    // peek() lets us see into the future
    assert_eq!(iter.peek(), Some(&&1));
    assert_eq!(iter.next(), Some(&1));

    assert_eq!(iter.next(), Some(&2));

    // we can peek() multiple times, the iterator won't advance
    assert_eq!(iter.peek(), Some(&&3));
    assert_eq!(iter.peek(), Some(&&3));

    assert_eq!(iter.next(), Some(&3));

    // after the iterator is finished, so is peek()
    assert_eq!(iter.peek(), None);
    assert_eq!(iter.next(), None);

Run

### `pub fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>ⓘ

### Notable traits for SkipWhile<I, P>

`impl<I, P> Iterator for SkipWhile<I, P> where
I: Iterator,
P: FnMut(&<I as Iterator>::Item) -> bool, type Item = <I as Iterator>::Item;`
where
P: FnMut(&Self::Item) -> bool,` [src]

Creates an iterator that `skip`s elements based on a predicate.

`skip_while()` takes a closure as an argument. It will call this closure on each element of the iterator, and ignore elements until it returns `false`.

After `false` is returned, `skip_while()`'s job is over, and the rest of the elements are yielded.

# Examples

Basic usage:

    let a = [-1i32, 0, 1];

    let mut iter = a.iter().skip_while(|x| x.is_negative());

    assert_eq!(iter.next(), Some(&0));
    assert_eq!(iter.next(), Some(&1));
    assert_eq!(iter.next(), None);

Run

Because the closure passed to `skip_while()` takes a reference, and many iterators iterate over references, this leads to a possibly confusing situation, where the type of the closure is a double reference:

    let a = [-1, 0, 1];

    let mut iter = a.iter().skip_while(|x| **x < 0); // need two *s!

    assert_eq!(iter.next(), Some(&0));
    assert_eq!(iter.next(), Some(&1));
    assert_eq!(iter.next(), None);

Run

Stopping after an initial `false`:

    let a = [-1, 0, 1, -2];

    let mut iter = a.iter().skip_while(|x| **x < 0);

    assert_eq!(iter.next(), Some(&0));
    assert_eq!(iter.next(), Some(&1));

    // while this would have been false, since we already got a false,
    // skip_while() isn't used any more
    assert_eq!(iter.next(), Some(&-2));

    assert_eq!(iter.next(), None);

Run

### `pub fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>ⓘ

### Notable traits for TakeWhile<I, P>

`impl<I, P> Iterator for TakeWhile<I, P> where
I: Iterator,
P: FnMut(&<I as Iterator>::Item) -> bool, type Item = <I as Iterator>::Item;`
where
P: FnMut(&Self::Item) -> bool,` [src]

Creates an iterator that yields elements based on a predicate.

`take_while()` takes a closure as an argument. It will call this closure on each element of the iterator, and yield elements while it returns `true`.

After `false` is returned, `take_while()`'s job is over, and the rest of the elements are ignored.

# Examples

Basic usage:

    let a = [-1i32, 0, 1];

    let mut iter = a.iter().take_while(|x| x.is_negative());

    assert_eq!(iter.next(), Some(&-1));
    assert_eq!(iter.next(), None);

Run

Because the closure passed to `take_while()` takes a reference, and many iterators iterate over references, this leads to a possibly confusing situation, where the type of the closure is a double reference:

    let a = [-1, 0, 1];

    let mut iter = a.iter().take_while(|x| **x < 0); // need two *s!

    assert_eq!(iter.next(), Some(&-1));
    assert_eq!(iter.next(), None);

Run

Stopping after an initial `false`:

    let a = [-1, 0, 1, -2];

    let mut iter = a.iter().take_while(|x| **x < 0);

    assert_eq!(iter.next(), Some(&-1));

    // We have more elements that are less than zero, but since we already
    // got a false, take_while() isn't used any more
    assert_eq!(iter.next(), None);

Run

Because `take_while()` needs to look at the value in order to see if it should be included or not, consuming iterators will see that it is removed:

    let a = [1, 2, 3, 4];
    let mut iter = a.iter();

    let result: Vec<i32> = iter.by_ref()
                               .take_while(|n| **n != 3)
                               .cloned()
                               .collect();

    assert_eq!(result, &[1, 2]);

    let result: Vec<i32> = iter.cloned().collect();

    assert_eq!(result, &[4]);

Run

The `3` is no longer there, because it was consumed in order to see if the iteration should stop, but wasn't placed back into the iterator.

### `pub fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>ⓘ

### Notable traits for MapWhile<I, P>

`impl<B, I, P> Iterator for MapWhile<I, P> where
I: Iterator,
P: FnMut(<I as Iterator>::Item) -> Option<B>, type Item = B;`
where
P: FnMut(Self::Item) -> Option<B>,` [src]

🔬 This is a nightly-only experimental API. (`iter_map_while` #68537)

recently added

Creates an iterator that both yields elements based on a predicate and maps.

`map_while()` takes a closure as an argument. It will call this closure on each element of the iterator, and yield elements while it returns `Some(_)`.

# Examples

Basic usage:

    #![feature(iter_map_while)]
    let a = [-1i32, 4, 0, 1];

    let mut iter = a.iter().map_while(|x| 16i32.checked_div(*x));

    assert_eq!(iter.next(), Some(-16));
    assert_eq!(iter.next(), Some(4));
    assert_eq!(iter.next(), None);

Run

Here's the same example, but with `take_while` and `map`:

    let a = [-1i32, 4, 0, 1];

    let mut iter = a.iter()
                    .map(|x| 16i32.checked_div(*x))
                    .take_while(|x| x.is_some())
                    .map(|x| x.unwrap());

    assert_eq!(iter.next(), Some(-16));
    assert_eq!(iter.next(), Some(4));
    assert_eq!(iter.next(), None);

Run

Stopping after an initial `None`:

    #![feature(iter_map_while)]
    use std::convert::TryFrom;

    let a = [0, 1, 2, -3, 4, 5, -6];

    let iter = a.iter().map_while(|x| u32::try_from(*x).ok());
    let vec = iter.collect::<Vec<_>>();

    // We have more elements which could fit in u32 (4, 5), but `map_while` returned `None` for `-3`
    // (as the `predicate` returned `None`) and `collect` stops at the first `None` encountered.
    assert_eq!(vec, vec![0, 1, 2]);

Run

Because `map_while()` needs to look at the value in order to see if it should be included or not, consuming iterators will see that it is removed:

    #![feature(iter_map_while)]
    use std::convert::TryFrom;

    let a = [1, 2, -3, 4];
    let mut iter = a.iter();

    let result: Vec<u32> = iter.by_ref()
                               .map_while(|n| u32::try_from(*n).ok())
                               .collect();

    assert_eq!(result, &[1, 2]);

    let result: Vec<i32> = iter.cloned().collect();

    assert_eq!(result, &[4]);

Run

The `-3` is no longer there, because it was consumed in order to see if the iteration should stop, but wasn't placed back into the iterator.

Note that unlike `take_while` this iterator is not fused. It is also not specified what this iterator returns after the first`None` is returned. If you need fused iterator, use `fuse`.

### `pub fn skip(self, n: usize) -> Skip<Self>ⓘ

### Notable traits for Skip<I>

`impl<I> Iterator for Skip<I> where
I: Iterator, type Item = <I as Iterator>::Item;`
`[src]

Creates an iterator that skips the first `n` elements.

After they have been consumed, the rest of the elements are yielded. Rather than overriding this method directly, instead override the `nth` method.

# Examples

Basic usage:

    let a = [1, 2, 3];

    let mut iter = a.iter().skip(2);

    assert_eq!(iter.next(), Some(&3));
    assert_eq!(iter.next(), None);

Run

### `pub fn take(self, n: usize) -> Take<Self>ⓘ

### Notable traits for Take<I>

`impl<I> Iterator for Take<I> where
I: Iterator, type Item = <I as Iterator>::Item;`
`[src]

Creates an iterator that yields its first `n` elements.

# Examples

Basic usage:

    let a = [1, 2, 3];

    let mut iter = a.iter().take(2);

    assert_eq!(iter.next(), Some(&1));
    assert_eq!(iter.next(), Some(&2));
    assert_eq!(iter.next(), None);

Run

`take()` is often used with an infinite iterator, to make it finite:

    let mut iter = (0..).take(3);

    assert_eq!(iter.next(), Some(0));
    assert_eq!(iter.next(), Some(1));
    assert_eq!(iter.next(), Some(2));
    assert_eq!(iter.next(), None);

Run

If less than `n` elements are available, `take` will limit itself to the size of the underlying iterator:

    let v = vec![1, 2];
    let mut iter = v.into_iter().take(5);
    assert_eq!(iter.next(), Some(1));
    assert_eq!(iter.next(), Some(2));
    assert_eq!(iter.next(), None);

Run

### `pub fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>ⓘ

### Notable traits for Scan<I, St, F>

`impl<B, I, St, F> Iterator for Scan<I, St, F> where
F: FnMut(&mut St, <I as Iterator>::Item) -> Option<B>,
I: Iterator, type Item = B;`
where
F: FnMut(&mut St, Self::Item) -> Option<B>,` [src]

An iterator adaptor similar to `fold` that holds internal state and produces a new iterator.

`scan()` takes two arguments: an initial value which seeds the internal state, and a closure with two arguments, the first being a mutable reference to the internal state and the second an iterator element. The closure can assign to the internal state to share state between iterations.

On iteration, the closure will be applied to each element of the iterator and the return value from the closure, an `Option`, is yielded by the iterator.

# Examples

Basic usage:

    let a = [1, 2, 3];

    let mut iter = a.iter().scan(1, |state, &x| {
        // each iteration, we'll multiply the state by the element
        *state = *state * x;

        // then, we'll yield the negation of the state
        Some(-*state)
    });

    assert_eq!(iter.next(), Some(-1));
    assert_eq!(iter.next(), Some(-2));
    assert_eq!(iter.next(), Some(-6));
    assert_eq!(iter.next(), None);

Run

### `pub fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>ⓘ

### Notable traits for FlatMap<I, U, F>

`impl<I, U, F> Iterator for FlatMap<I, U, F> where
F: FnMut(<I as Iterator>::Item) -> U,
I: Iterator,
U: IntoIterator, type Item = <U as IntoIterator>::Item;`
where
F: FnMut(Self::Item) -> U,
U: IntoIterator,` [src]

Creates an iterator that works like map, but flattens nested structure.

The `map` adapter is very useful, but only when the closure argument produces values. If it produces an iterator instead, there's an extra layer of indirection. `flat_map()` will remove this extra layer on its own.

You can think of `flat_map(f)` as the semantic equivalent of `map`ping, and then `flatten`ing as in `map(f).flatten()`.

Another way of thinking about `flat_map()`: `map`'s closure returns one item for each element, and `flat_map()`'s closure returns an iterator for each element.

# Examples

Basic usage:

    let words = ["alpha", "beta", "gamma"];

    // chars() returns an iterator
    let merged: String = words.iter()
                              .flat_map(|s| s.chars())
                              .collect();
    assert_eq!(merged, "alphabetagamma");

Run

### `pub fn flatten(self) -> Flatten<Self>ⓘ

### Notable traits for Flatten<I>

`impl<I, U> Iterator for Flatten<I> where
I: Iterator,
U: Iterator,
<I as Iterator>::Item: IntoIterator,
<<I as Iterator>::Item as IntoIterator>::IntoIter == U,
<<I as Iterator>::Item as IntoIterator>::Item == <U as Iterator>::Item, type Item = <U as Iterator>::Item;`
where
Self::Item: IntoIterator,` 1.29.0[src]

Creates an iterator that flattens nested structure.

This is useful when you have an iterator of iterators or an iterator of things that can be turned into iterators and you want to remove one level of indirection.

# Examples

Basic usage:

    let data = vec![vec![1, 2, 3, 4], vec![5, 6]];
    let flattened = data.into_iter().flatten().collect::<Vec<u8>>();
    assert_eq!(flattened, &[1, 2, 3, 4, 5, 6]);

Run

Mapping and then flattening:

    let words = ["alpha", "beta", "gamma"];

    // chars() returns an iterator
    let merged: String = words.iter()
                              .map(|s| s.chars())
                              .flatten()
                              .collect();
    assert_eq!(merged, "alphabetagamma");

Run

You can also rewrite this in terms of `flat_map()`, which is preferable in this case since it conveys intent more clearly:

    let words = ["alpha", "beta", "gamma"];

    // chars() returns an iterator
    let merged: String = words.iter()
                              .flat_map(|s| s.chars())
                              .collect();
    assert_eq!(merged, "alphabetagamma");

Run

Flattening once only removes one level of nesting:

    let d3 = [[[1, 2], [3, 4]], [[5, 6], [7, 8]]];

    let d2 = d3.iter().flatten().collect::<Vec<_>>();
    assert_eq!(d2, [&[1, 2], &[3, 4], &[5, 6], &[7, 8]]);

    let d1 = d3.iter().flatten().flatten().collect::<Vec<_>>();
    assert_eq!(d1, [&1, &2, &3, &4, &5, &6, &7, &8]);

Run

Here we see that `flatten()` does not perform a "deep" flatten. Instead, only one level of nesting is removed. That is, if you `flatten()` a three-dimensional array the result will be two-dimensional and not one-dimensional. To get a one-dimensional structure, you have to `flatten()` again.

### `pub fn fuse(self) -> Fuse<Self>ⓘ

### Notable traits for Fuse<I>

`impl<I> Iterator for Fuse<I> where
I: Iterator, type Item = <I as Iterator>::Item;`
`[src]

Creates an iterator which ends after the first `None`.

After an iterator returns `None`, future calls may or may not yield `Some(T)` again. `fuse()` adapts an iterator, ensuring that after a `None` is given, it will always return `None` forever.

# Examples

Basic usage:

    // an iterator which alternates between Some and None
    struct Alternate {
        state: i32,
    }

    impl Iterator for Alternate {
        type Item = i32;

        fn next(&mut self) -> Option<i32> {
            let val = self.state;
            self.state = self.state + 1;

            // if it's even, Some(i32), else None
            if val % 2 == 0 {
                Some(val)
            } else {
                None
            }
        }
    }

    let mut iter = Alternate { state: 0 };

    // we can see our iterator going back and forth
    assert_eq!(iter.next(), Some(0));
    assert_eq!(iter.next(), None);
    assert_eq!(iter.next(), Some(2));
    assert_eq!(iter.next(), None);

    // however, once we fuse it...
    let mut iter = iter.fuse();

    assert_eq!(iter.next(), Some(4));
    assert_eq!(iter.next(), None);

    // it will always return `None` after the first time.
    assert_eq!(iter.next(), None);
    assert_eq!(iter.next(), None);
    assert_eq!(iter.next(), None);

Run

### `pub fn inspect<F>(self, f: F) -> Inspect<Self, F>ⓘ

### Notable traits for Inspect<I, F>

`impl<I, F> Iterator for Inspect<I, F> where
F: FnMut(&<I as Iterator>::Item),
I: Iterator, type Item = <I as Iterator>::Item;`
where
F: FnMut(&Self::Item),` [src]

Does something with each element of an iterator, passing the value on.

When using iterators, you'll often chain several of them together. While working on such code, you might want to check out what's happening at various parts in the pipeline. To do that, insert a call to `inspect()`.

It's more common for `inspect()` to be used as a debugging tool than to exist in your final code, but applications may find it useful in certain situations when errors need to be logged before being discarded.

# Examples

Basic usage:

    let a = [1, 4, 2, 3];

    // this iterator sequence is complex.
    let sum = a.iter()
        .cloned()
        .filter(|x| x % 2 == 0)
        .fold(0, |sum, i| sum + i);

    println!("{}", sum);

    // let's add some inspect() calls to investigate what's happening
    let sum = a.iter()
        .cloned()
        .inspect(|x| println!("about to filter: {}", x))
        .filter(|x| x % 2 == 0)
        .inspect(|x| println!("made it through filter: {}", x))
        .fold(0, |sum, i| sum + i);

    println!("{}", sum);

Run

This will print:

    6
    about to filter: 1
    about to filter: 4
    made it through filter: 4
    about to filter: 2
    made it through filter: 2
    about to filter: 3
    6

Logging errors before discarding them:

    let lines = ["1", "2", "a"];

    let sum: i32 = lines
        .iter()
        .map(|line| line.parse::<i32>())
        .inspect(|num| {
            if let Err(ref e) = *num {
                println!("Parsing error: {}", e);
            }
        })
        .filter_map(Result::ok)
        .sum();

    println!("Sum: {}", sum);

Run

This will print:

    Parsing error: invalid digit found in string
    Sum: 3

### `pub fn by_ref(&mut self) -> &mut Selfⓘ

### Notable traits for &'_ mut F

`impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized, '_> Read for &'_ mut Rimpl<W: Write + ?Sized, '_> Write for &'_ mut W`
`[src]

Borrows an iterator, rather than consuming it.

This is useful to allow applying iterator adaptors while still retaining ownership of the original iterator.

# Examples

Basic usage:

    let a = [1, 2, 3];

    let iter = a.iter();

    let sum: i32 = iter.take(5).fold(0, |acc, i| acc + i);

    assert_eq!(sum, 6);

    // if we try to use iter again, it won't work. The following line
    // gives "error: use of moved value: `iter`
    // assert_eq!(iter.next(), None);

    // let's try that again
    let a = [1, 2, 3];

    let mut iter = a.iter();

    // instead, we add in a .by_ref()
    let sum: i32 = iter.by_ref().take(2).fold(0, |acc, i| acc + i);

    assert_eq!(sum, 3);

    // now this is just fine:
    assert_eq!(iter.next(), Some(&3));
    assert_eq!(iter.next(), None);

Run

### `#[must_use = "if you really need to exhaust the iterator, consider `.for_each(drop)` instead"]pub fn collect<B>(self) -> B where
B: FromIterator<Self::Item>,` [src]

Transforms an iterator into a collection.

`collect()` can take anything iterable, and turn it into a relevant collection. This is one of the more powerful methods in the standard library, used in a variety of contexts.

The most basic pattern in which `collect()` is used is to turn one collection into another. You take a collection, call `iter` on it, do a bunch of transformations, and then `collect()` at the end.

`collect()` can also create instances of types that are not typical collections. For example, a `String` can be built from `char`s, and an iterator of `Result<T, E>` items can be collected into `Result<Collection<T>, E>`. See the examples below for more.

Because `collect()` is so general, it can cause problems with type inference. As such, `collect()` is one of the few times you'll see the syntax affectionately known as the 'turbofish': `::<>`. This helps the inference algorithm understand specifically which collection you're trying to collect into.

# Examples

Basic usage:

    let a = [1, 2, 3];

    let doubled: Vec<i32> = a.iter()
                             .map(|&x| x * 2)
                             .collect();

    assert_eq!(vec![2, 4, 6], doubled);

Run

Note that we needed the `: Vec<i32>` on the left-hand side. This is because we could collect into, for example, a `VecDeque<T>` instead:

    use std::collections::VecDeque;

    let a = [1, 2, 3];

    let doubled: VecDeque<i32> = a.iter().map(|&x| x * 2).collect();

    assert_eq!(2, doubled[0]);
    assert_eq!(4, doubled[1]);
    assert_eq!(6, doubled[2]);

Run

Using the 'turbofish' instead of annotating `doubled`:

    let a = [1, 2, 3];

    let doubled = a.iter().map(|x| x * 2).collect::<Vec<i32>>();

    assert_eq!(vec![2, 4, 6], doubled);

Run

Because `collect()` only cares about what you're collecting into, you can still use a partial type hint, `_`, with the turbofish:

    let a = [1, 2, 3];

    let doubled = a.iter().map(|x| x * 2).collect::<Vec<_>>();

    assert_eq!(vec![2, 4, 6], doubled);

Run

Using `collect()` to make a `String`:

    let chars = ['g', 'd', 'k', 'k', 'n'];

    let hello: String = chars.iter()
        .map(|&x| x as u8)
        .map(|x| (x + 1) as char)
        .collect();

    assert_eq!("hello", hello);

Run

If you have a list of `Result<T, E>`s, you can use `collect()` to see if any of them failed:

    let results = [Ok(1), Err("nope"), Ok(3), Err("bad")];

    let result: Result<Vec<_>, &str> = results.iter().cloned().collect();

    // gives us the first error
    assert_eq!(Err("nope"), result);

    let results = [Ok(1), Ok(3)];

    let result: Result<Vec<_>, &str> = results.iter().cloned().collect();

    // gives us the list of answers
    assert_eq!(Ok(vec![1, 3]), result);

Run

### `pub fn partition<B, F>(self, f: F) -> (B, B) where
B: Default + Extend<Self::Item>,
F: FnMut(&Self::Item) -> bool,` [src]

Consumes an iterator, creating two collections from it.

The predicate passed to `partition()` can return `true`, or `false`. `partition()` returns a pair, all of the elements for which it returned `true`, and all of the elements for which it returned `false`.

See also `is_partitioned()` and `partition_in_place()`.

# Examples

Basic usage:

    let a = [1, 2, 3];

    let (even, odd): (Vec<i32>, Vec<i32>) = a
        .iter()
        .partition(|&n| n % 2 == 0);

    assert_eq!(even, vec![2]);
    assert_eq!(odd, vec![1, 3]);

Run

### `pub fn partition_in_place<'a, T, P>(self, predicate: P) -> usize where
P: FnMut(&T) -> bool,
Self: DoubleEndedIterator<Item = &'a mut T>,
T: 'a,` [src]

🔬 This is a nightly-only experimental API. (`iter_partition_in_place` #62543)

new API

Reorders the elements of this iterator in-place according to the given predicate, such that all those that return `true` precede all those that return `false`. Returns the number of `true` elements found.

The relative order of partitioned items is not maintained.

See also `is_partitioned()` and `partition()`.

# Examples

    #![feature(iter_partition_in_place)]

    let mut a = [1, 2, 3, 4, 5, 6, 7];

    // Partition in-place between evens and odds
    let i = a.iter_mut().partition_in_place(|&n| n % 2 == 0);

    assert_eq!(i, 3);
    assert!(a[..i].iter().all(|&n| n % 2 == 0)); // evens
    assert!(a[i..].iter().all(|&n| n % 2 == 1)); // odds

Run

### `pub fn is_partitioned<P>(self, predicate: P) -> bool where
P: FnMut(Self::Item) -> bool,` [src]

🔬 This is a nightly-only experimental API. (`iter_is_partitioned` #62544)

new API

Checks if the elements of this iterator are partitioned according to the given predicate, such that all those that return `true` precede all those that return `false`.

See also `partition()` and `partition_in_place()`.

# Examples

    #![feature(iter_is_partitioned)]

    assert!("Iterator".chars().is_partitioned(char::is_uppercase));
    assert!(!"IntoIterator".chars().is_partitioned(char::is_uppercase));

Run

### `pub fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
F: FnMut(B, Self::Item) -> R,
R: Try<Ok = B>,` 1.27.0[src]

An iterator method that applies a function as long as it returns successfully, producing a single, final value.

`try_fold()` takes two arguments: an initial value, and a closure with two arguments: an 'accumulator', and an element. The closure either returns successfully, with the value that the accumulator should have for the next iteration, or it returns failure, with an error value that is propagated back to the caller immediately (short-circuiting).

The initial value is the value the accumulator will have on the first call. If applying the closure succeeded against every element of the iterator, `try_fold()` returns the final accumulator as success.

Folding is useful whenever you have a collection of something, and want to produce a single value from it.

# Note to Implementors

Several of the other (forward) methods have default implementations in terms of this one, so try to implement this explicitly if it can do something better than the default `for` loop implementation.

In particular, try to have this call `try_fold()` on the internal parts from which this iterator is composed. If multiple calls are needed, the `?` operator may be convenient for chaining the accumulator value along, but beware any invariants that need to be upheld before those early returns. This is a `&mut self` method, so iteration needs to be resumable after hitting an error here.

# Examples

Basic usage:

    let a = [1, 2, 3];

    // the checked sum of all of the elements of the array
    let sum = a.iter().try_fold(0i8, |acc, &x| acc.checked_add(x));

    assert_eq!(sum, Some(6));

Run

Short-circuiting:

    let a = [10, 20, 30, 100, 40, 50];
    let mut it = a.iter();

    // This sum overflows when adding the 100 element
    let sum = it.try_fold(0i8, |acc, &x| acc.checked_add(x));
    assert_eq!(sum, None);

    // Because it short-circuited, the remaining elements are still
    // available through the iterator.
    assert_eq!(it.len(), 2);
    assert_eq!(it.next(), Some(&40));

Run

### `pub fn try_for_each<F, R>(&mut self, f: F) -> R where
F: FnMut(Self::Item) -> R,
R: Try<Ok = ()>,` 1.27.0[src]

An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error.

This can also be thought of as the fallible form of `for_each()` or as the stateless version of `try_fold()`.

# Examples

    use std::fs::rename;
    use std::io::{stdout, Write};
    use std::path::Path;

    let data = ["no_tea.txt", "stale_bread.json", "torrential_rain.png"];

    let res = data.iter().try_for_each(|x| writeln!(stdout(), "{}", x));
    assert!(res.is_ok());

    let mut it = data.iter().cloned();
    let res = it.try_for_each(|x| rename(x, Path::new(x).with_extension("old")));
    assert!(res.is_err());
    // It short-circuited, so the remaining items are still in the iterator:
    assert_eq!(it.next(), Some("stale_bread.json"));

Run

### `pub fn fold<B, F>(self, init: B, f: F) -> B where
F: FnMut(B, Self::Item) -> B,` [src]

An iterator method that applies a function, producing a single, final value.

`fold()` takes two arguments: an initial value, and a closure with two arguments: an 'accumulator', and an element. The closure returns the value that the accumulator should have for the next iteration.

The initial value is the value the accumulator will have on the first call.

After applying this closure to every element of the iterator, `fold()` returns the accumulator.

This operation is sometimes called 'reduce' or 'inject'.

Folding is useful whenever you have a collection of something, and want to produce a single value from it.

Note: `fold()`, and similar methods that traverse the entire iterator, may not terminate for infinite iterators, even on traits for which a result is determinable in finite time.

# Note to Implementors

Several of the other (forward) methods have default implementations in terms of this one, so try to implement this explicitly if it can do something better than the default `for` loop implementation.

In particular, try to have this call `fold()` on the internal parts from which this iterator is composed.

# Examples

Basic usage:

    let a = [1, 2, 3];

    // the sum of all of the elements of the array
    let sum = a.iter().fold(0, |acc, x| acc + x);

    assert_eq!(sum, 6);

Run

Let's walk through each step of the iteration here:

element | acc | x | result
--- | --- | --- | ---
| 0 |  |
1 | 0 | 1 | 1
2 | 1 | 2 | 3
3 | 3 | 3 | 6

And so, our final result, `6`.

It's common for people who haven't used iterators a lot to use a `for` loop with a list of things to build up a result. Those can be turned into `fold()`s:

    let numbers = [1, 2, 3, 4, 5];

    let mut result = 0;

    // for loop:
    for i in &numbers {
        result = result + i;
    }

    // fold:
    let result2 = numbers.iter().fold(0, |acc, &x| acc + x);

    // they're the same
    assert_eq!(result, result2);

Run

### `pub fn fold_first<F>(self, f: F) -> Option<Self::Item> where
F: FnMut(Self::Item, Self::Item) -> Self::Item,` [src]

🔬 This is a nightly-only experimental API. (`iterator_fold_self` #68125)

The same as `fold()`, but uses the first element in the iterator as the initial value, folding every subsequent element into it. If the iterator is empty, return `None`; otherwise, return the result of the fold.

# Example

Find the maximum value:

    #![feature(iterator_fold_self)]

    fn find_max<I>(iter: I) -> Option<I::Item>
        where I: Iterator,
              I::Item: Ord,
    {
        iter.fold_first(|a, b| {
            if a >= b { a } else { b }
        })
    }
    let a = [10, 20, 5, -23, 0];
    let b: [u32; 0] = [];

    assert_eq!(find_max(a.iter()), Some(&20));
    assert_eq!(find_max(b.iter()), None);

Run

### `pub fn all<F>(&mut self, f: F) -> bool where
F: FnMut(Self::Item) -> bool,` [src]

Tests if every element of the iterator matches a predicate.

`all()` takes a closure that returns `true` or `false`. It applies this closure to each element of the iterator, and if they all return `true`, then so does `all()`. If any of them return `false`, it returns `false`.

`all()` is short-circuiting; in other words, it will stop processing as soon as it finds a `false`, given that no matter what else happens, the result will also be `false`.

An empty iterator returns `true`.

# Examples

Basic usage:

    let a = [1, 2, 3];

    assert!(a.iter().all(|&x| x > 0));

    assert!(!a.iter().all(|&x| x > 2));

Run

Stopping at the first `false`:

    let a = [1, 2, 3];

    let mut iter = a.iter();

    assert!(!iter.all(|&x| x != 2));

    // we can still use `iter`, as there are more elements.
    assert_eq!(iter.next(), Some(&3));

Run

### `pub fn any<F>(&mut self, f: F) -> bool where
F: FnMut(Self::Item) -> bool,` [src]

Tests if any element of the iterator matches a predicate.

`any()` takes a closure that returns `true` or `false`. It applies this closure to each element of the iterator, and if any of them return `true`, then so does `any()`. If they all return `false`, it returns `false`.

`any()` is short-circuiting; in other words, it will stop processing as soon as it finds a `true`, given that no matter what else happens, the result will also be `true`.

An empty iterator returns `false`.

# Examples

Basic usage:

    let a = [1, 2, 3];

    assert!(a.iter().any(|&x| x > 0));

    assert!(!a.iter().any(|&x| x > 5));

Run

Stopping at the first `true`:

    let a = [1, 2, 3];

    let mut iter = a.iter();

    assert!(iter.any(|&x| x != 2));

    // we can still use `iter`, as there are more elements.
    assert_eq!(iter.next(), Some(&2));

Run

### `pub fn find<P>(&mut self, predicate: P) -> Option<Self::Item> where
P: FnMut(&Self::Item) -> bool,` [src]

Searches for an element of an iterator that satisfies a predicate.

`find()` takes a closure that returns `true` or `false`. It applies this closure to each element of the iterator, and if any of them return `true`, then `find()` returns `Some(element)`. If they all return `false`, it returns `None`.

`find()` is short-circuiting; in other words, it will stop processing as soon as the closure returns `true`.

Because `find()` takes a reference, and many iterators iterate over references, this leads to a possibly confusing situation where the argument is a double reference. You can see this effect in the examples below, with `&&x`.

# Examples

Basic usage:

    let a = [1, 2, 3];

    assert_eq!(a.iter().find(|&&x| x == 2), Some(&2));

    assert_eq!(a.iter().find(|&&x| x == 5), None);

Run

Stopping at the first `true`:

    let a = [1, 2, 3];

    let mut iter = a.iter();

    assert_eq!(iter.find(|&&x| x == 2), Some(&2));

    // we can still use `iter`, as there are more elements.
    assert_eq!(iter.next(), Some(&3));

Run

Note that `iter.find(f)` is equivalent to `iter.filter(f).next()`.

### `pub fn find_map<B, F>(&mut self, f: F) -> Option<B> where
F: FnMut(Self::Item) -> Option<B>,` 1.30.0[src]

Applies function to the elements of iterator and returns the first non-none result.

`iter.find_map(f)` is equivalent to `iter.filter_map(f).next()`.

# Examples

    let a = ["lol", "NaN", "2", "5"];

    let first_number = a.iter().find_map(|s| s.parse().ok());

    assert_eq!(first_number, Some(2));

Run

### `pub fn try_find<F, R>(
&mut self,
f: F
) -> Result<Option<Self::Item>, <R as Try>::Error> where
F: FnMut(&Self::Item) -> R,
R: Try<Ok = bool>,` [src]

🔬 This is a nightly-only experimental API. (`try_find` #63178)

new API

Applies function to the elements of iterator and returns the first true result or the first error.

# Examples

    #![feature(try_find)]

    let a = ["1", "2", "lol", "NaN", "5"];

    let is_my_num = |s: &str, search: i32| -> Result<bool, std::num::ParseIntError> {
        Ok(s.parse::<i32>()?  == search)
    };

    let result = a.iter().try_find(|&&s| is_my_num(s, 2));
    assert_eq!(result, Ok(Some(&"2")));

    let result = a.iter().try_find(|&&s| is_my_num(s, 5));
    assert!(result.is_err());

Run

### `pub fn position<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(Self::Item) -> bool,` [src]

Searches for an element in an iterator, returning its index.

`position()` takes a closure that returns `true` or `false`. It applies this closure to each element of the iterator, and if one of them returns `true`, then `position()` returns `Some(index)`. If all of them return `false`, it returns `None`.

`position()` is short-circuiting; in other words, it will stop processing as soon as it finds a `true`.

# Overflow Behavior

The method does no guarding against overflows, so if there are more than `usize::MAX` non-matching elements, it either produces the wrong result or panics. If debug assertions are enabled, a panic is guaranteed.

# Panics

This function might panic if the iterator has more than `usize::MAX` non-matching elements.

# Examples

Basic usage:

    let a = [1, 2, 3];

    assert_eq!(a.iter().position(|&x| x == 2), Some(1));

    assert_eq!(a.iter().position(|&x| x == 5), None);

Run

Stopping at the first `true`:

    let a = [1, 2, 3, 4];

    let mut iter = a.iter();

    assert_eq!(iter.position(|&x| x >= 2), Some(1));

    // we can still use `iter`, as there are more elements.
    assert_eq!(iter.next(), Some(&3));

    // The returned index depends on iterator state
    assert_eq!(iter.position(|&x| x == 4), Some(0));

Run

### `pub fn rposition<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(Self::Item) -> bool,
Self: ExactSizeIterator + DoubleEndedIterator,` [src]

Searches for an element in an iterator from the right, returning its index.

`rposition()` takes a closure that returns `true` or `false`. It applies this closure to each element of the iterator, starting from the end, and if one of them returns `true`, then `rposition()` returns `Some(index)`. If all of them return `false`, it returns `None`.

`rposition()` is short-circuiting; in other words, it will stop processing as soon as it finds a `true`.

# Examples

Basic usage:

    let a = [1, 2, 3];

    assert_eq!(a.iter().rposition(|&x| x == 3), Some(2));

    assert_eq!(a.iter().rposition(|&x| x == 5), None);

Run

Stopping at the first `true`:

    let a = [1, 2, 3];

    let mut iter = a.iter();

    assert_eq!(iter.rposition(|&x| x == 2), Some(1));

    // we can still use `iter`, as there are more elements.
    assert_eq!(iter.next(), Some(&1));

Run

### `pub fn max(self) -> Option<Self::Item> where
Self::Item: Ord,` [src]

Returns the maximum element of an iterator.

If several elements are equally maximum, the last element is returned. If the iterator is empty, `None` is returned.

# Examples

Basic usage:

    let a = [1, 2, 3];
    let b: Vec<u32> = Vec::new();

    assert_eq!(a.iter().max(), Some(&3));
    assert_eq!(b.iter().max(), None);

Run

### `pub fn min(self) -> Option<Self::Item> where
Self::Item: Ord,` [src]

Returns the minimum element of an iterator.

If several elements are equally minimum, the first element is returned. If the iterator is empty, `None` is returned.

# Examples

Basic usage:

    let a = [1, 2, 3];
    let b: Vec<u32> = Vec::new();

    assert_eq!(a.iter().min(), Some(&1));
    assert_eq!(b.iter().min(), None);

Run

### `pub fn max_by_key<B, F>(self, f: F) -> Option<Self::Item> where
B: Ord,
F: FnMut(&Self::Item) -> B,` 1.6.0[src]

Returns the element that gives the maximum value from the specified function.

If several elements are equally maximum, the last element is returned. If the iterator is empty, `None` is returned.

# Examples

    let a = [-3_i32, 0, 1, 5, -10];
    assert_eq!(*a.iter().max_by_key(|x| x.abs()).unwrap(), -10);

Run

### `pub fn max_by<F>(self, compare: F) -> Option<Self::Item> where
F: FnMut(&Self::Item, &Self::Item) -> Ordering,` 1.15.0[src]

Returns the element that gives the maximum value with respect to the specified comparison function.

If several elements are equally maximum, the last element is returned. If the iterator is empty, `None` is returned.

# Examples

    let a = [-3_i32, 0, 1, 5, -10];
    assert_eq!(*a.iter().max_by(|x, y| x.cmp(y)).unwrap(), 5);

Run

### `pub fn min_by_key<B, F>(self, f: F) -> Option<Self::Item> where
B: Ord,
F: FnMut(&Self::Item) -> B,` 1.6.0[src]

Returns the element that gives the minimum value from the specified function.

If several elements are equally minimum, the first element is returned. If the iterator is empty, `None` is returned.

# Examples

    let a = [-3_i32, 0, 1, 5, -10];
    assert_eq!(*a.iter().min_by_key(|x| x.abs()).unwrap(), 0);

Run

### `pub fn min_by<F>(self, compare: F) -> Option<Self::Item> where
F: FnMut(&Self::Item, &Self::Item) -> Ordering,` 1.15.0[src]

Returns the element that gives the minimum value with respect to the specified comparison function.

If several elements are equally minimum, the first element is returned. If the iterator is empty, `None` is returned.

# Examples

    let a = [-3_i32, 0, 1, 5, -10];
    assert_eq!(*a.iter().min_by(|x, y| x.cmp(y)).unwrap(), -10);

Run

### `pub fn rev(self) -> Rev<Self>ⓘ

### Notable traits for Rev<I>

`impl<I> Iterator for Rev<I> where
I: DoubleEndedIterator, type Item = <I as Iterator>::Item;`
where
Self: DoubleEndedIterator,` [src]

Reverses an iterator's direction.

Usually, iterators iterate from left to right. After using `rev()`, an iterator will instead iterate from right to left.

This is only possible if the iterator has an end, so `rev()` only works on `DoubleEndedIterator`s.

# Examples

    let a = [1, 2, 3];

    let mut iter = a.iter().rev();

    assert_eq!(iter.next(), Some(&3));
    assert_eq!(iter.next(), Some(&2));
    assert_eq!(iter.next(), Some(&1));

    assert_eq!(iter.next(), None);

Run

### `pub fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB) where
FromA: Default + Extend<A>,
FromB: Default + Extend<B>,
Self: Iterator<Item = (A, B)>,` [src]

Converts an iterator of pairs into a pair of containers.

`unzip()` consumes an entire iterator of pairs, producing two collections: one from the left elements of the pairs, and one from the right elements.

This function is, in some sense, the opposite of `zip`.

# Examples

Basic usage:

    let a = [(1, 2), (3, 4)];

    let (left, right): (Vec<_>, Vec<_>) = a.iter().cloned().unzip();

    assert_eq!(left, [1, 3]);
    assert_eq!(right, [2, 4]);

Run

### `pub fn copied<'a, T>(self) -> Copied<Self>ⓘ

### Notable traits for Copied<I>

`impl<'a, I, T> Iterator for Copied<I> where
I: Iterator<Item = &'a T>,
T: 'a + Copy, type Item = T;`
where
Self: Iterator<Item = &'a T>,
T: 'a + Copy,` 1.36.0[src]

Creates an iterator which copies all of its elements.

This is useful when you have an iterator over `&T`, but you need an iterator over `T`.

# Examples

Basic usage:

    let a = [1, 2, 3];

    let v_copied: Vec<_> = a.iter().copied().collect();

    // copied is the same as .map(|&x| x)
    let v_map: Vec<_> = a.iter().map(|&x| x).collect();

    assert_eq!(v_copied, vec![1, 2, 3]);
    assert_eq!(v_map, vec![1, 2, 3]);

Run

### `pub fn cloned<'a, T>(self) -> Cloned<Self>ⓘ

### Notable traits for Cloned<I>

`impl<'a, I, T> Iterator for Cloned<I> where
I: Iterator<Item = &'a T>,
T: 'a + Clone, type Item = T;`
where
Self: Iterator<Item = &'a T>,
T: 'a + Clone,` [src]

Creates an iterator which `clone`s all of its elements.

This is useful when you have an iterator over `&T`, but you need an iterator over `T`.

# Examples

Basic usage:

    let a = [1, 2, 3];

    let v_cloned: Vec<_> = a.iter().cloned().collect();

    // cloned is the same as .map(|&x| x), for integers
    let v_map: Vec<_> = a.iter().map(|&x| x).collect();

    assert_eq!(v_cloned, vec![1, 2, 3]);
    assert_eq!(v_map, vec![1, 2, 3]);

Run

### `pub fn cycle(self) -> Cycle<Self>ⓘ

### Notable traits for Cycle<I>

`impl<I> Iterator for Cycle<I> where
I: Clone + Iterator, type Item = <I as Iterator>::Item;`
where
Self: Clone,` [src]

Repeats an iterator endlessly.

Instead of stopping at `None`, the iterator will instead start again, from the beginning. After iterating again, it will start at the beginning again. And again. And again. Forever.

# Examples

Basic usage:

    let a = [1, 2, 3];

    let mut it = a.iter().cycle();

    assert_eq!(it.next(), Some(&1));
    assert_eq!(it.next(), Some(&2));
    assert_eq!(it.next(), Some(&3));
    assert_eq!(it.next(), Some(&1));
    assert_eq!(it.next(), Some(&2));
    assert_eq!(it.next(), Some(&3));
    assert_eq!(it.next(), Some(&1));

Run

### `pub fn sum<S>(self) -> S where
S: Sum<Self::Item>,` 1.11.0[src]

Sums the elements of an iterator.

Takes each element, adds them together, and returns the result.

An empty iterator returns the zero value of the type.

# Panics

When calling `sum()` and a primitive integer type is being returned, this method will panic if the computation overflows and debug assertions are enabled.

# Examples

Basic usage:

    let a = [1, 2, 3];
    let sum: i32 = a.iter().sum();

    assert_eq!(sum, 6);

Run

### `pub fn product<P>(self) -> P where
P: Product<Self::Item>,` 1.11.0[src]

Iterates over the entire iterator, multiplying all the elements

An empty iterator returns the one value of the type.

# Panics

When calling `product()` and a primitive integer type is being returned, method will panic if the computation overflows and debug assertions are enabled.

# Examples

    fn factorial(n: u32) -> u32 {
        (1..=n).product()
    }
    assert_eq!(factorial(0), 1);
    assert_eq!(factorial(1), 1);
    assert_eq!(factorial(5), 120);

Run

### `pub fn cmp<I>(self, other: I) -> Ordering where
I: IntoIterator<Item = Self::Item>,
Self::Item: Ord,` 1.5.0[src]

Lexicographically compares the elements of this `Iterator` with those of another.

# Examples

    use std::cmp::Ordering;

    assert_eq!([1].iter().cmp([1].iter()), Ordering::Equal);
    assert_eq!([1].iter().cmp([1, 2].iter()), Ordering::Less);
    assert_eq!([1, 2].iter().cmp([1].iter()), Ordering::Greater);

Run

### `pub fn cmp_by<I, F>(self, other: I, cmp: F) -> Ordering where
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,
I: IntoIterator,` [src]

🔬 This is a nightly-only experimental API. (`iter_order_by` #64295)

Lexicographically compares the elements of this `Iterator` with those of another with respect to the specified comparison function.

# Examples

Basic usage:

    #![feature(iter_order_by)]

    use std::cmp::Ordering;

    let xs = [1, 2, 3, 4];
    let ys = [1, 4, 9, 16];

    assert_eq!(xs.iter().cmp_by(&ys, |&x, &y| x.cmp(&y)), Ordering::Less);
    assert_eq!(xs.iter().cmp_by(&ys, |&x, &y| (x * x).cmp(&y)), Ordering::Equal);
    assert_eq!(xs.iter().cmp_by(&ys, |&x, &y| (2 * x).cmp(&y)), Ordering::Greater);

Run

### `pub fn partial_cmp<I>(self, other: I) -> Option<Ordering> where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,` 1.5.0[src]

Lexicographically compares the elements of this `Iterator` with those of another.

# Examples

    use std::cmp::Ordering;

    assert_eq!([1.].iter().partial_cmp([1.].iter()), Some(Ordering::Equal));
    assert_eq!([1.].iter().partial_cmp([1., 2.].iter()), Some(Ordering::Less));
    assert_eq!([1., 2.].iter().partial_cmp([1.].iter()), Some(Ordering::Greater));

    assert_eq!([f64::NAN].iter().partial_cmp([1.].iter()), None);

Run

### `pub fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering> where
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,
I: IntoIterator,` [src]

🔬 This is a nightly-only experimental API. (`iter_order_by` #64295)

Lexicographically compares the elements of this `Iterator` with those of another with respect to the specified comparison function.

# Examples

Basic usage:

    #![feature(iter_order_by)]

    use std::cmp::Ordering;

    let xs = [1.0, 2.0, 3.0, 4.0];
    let ys = [1.0, 4.0, 9.0, 16.0];

    assert_eq!(
        xs.iter().partial_cmp_by(&ys, |&x, &y| x.partial_cmp(&y)),
        Some(Ordering::Less)
    );
    assert_eq!(
        xs.iter().partial_cmp_by(&ys, |&x, &y| (x * x).partial_cmp(&y)),
        Some(Ordering::Equal)
    );
    assert_eq!(
        xs.iter().partial_cmp_by(&ys, |&x, &y| (2.0 * x).partial_cmp(&y)),
        Some(Ordering::Greater)
    );

Run

### `pub fn eq<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,` 1.5.0[src]

Determines if the elements of this `Iterator` are equal to those of another.

# Examples

    assert_eq!([1].iter().eq([1].iter()), true);
    assert_eq!([1].iter().eq([1, 2].iter()), false);

Run

### `pub fn eq_by<I, F>(self, other: I, eq: F) -> bool where
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,
I: IntoIterator,` [src]

🔬 This is a nightly-only experimental API. (`iter_order_by` #64295)

Determines if the elements of this `Iterator` are equal to those of another with respect to the specified equality function.

# Examples

Basic usage:

    #![feature(iter_order_by)]

    let xs = [1, 2, 3, 4];
    let ys = [1, 4, 9, 16];

    assert!(xs.iter().eq_by(&ys, |&x, &y| x * x == y));

Run

### `pub fn ne<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,` 1.5.0[src]

Determines if the elements of this `Iterator` are unequal to those of another.

# Examples

    assert_eq!([1].iter().ne([1].iter()), false);
    assert_eq!([1].iter().ne([1, 2].iter()), true);

Run

### `pub fn lt<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,` 1.5.0[src]

Determines if the elements of this `Iterator` are lexicographically less than those of another.

# Examples

    assert_eq!([1].iter().lt([1].iter()), false);
    assert_eq!([1].iter().lt([1, 2].iter()), true);
    assert_eq!([1, 2].iter().lt([1].iter()), false);
    assert_eq!([1, 2].iter().lt([1, 2].iter()), false);

Run

### `pub fn le<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,` 1.5.0[src]

Determines if the elements of this `Iterator` are lexicographically less or equal to those of another.

# Examples

    assert_eq!([1].iter().le([1].iter()), true);
    assert_eq!([1].iter().le([1, 2].iter()), true);
    assert_eq!([1, 2].iter().le([1].iter()), false);
    assert_eq!([1, 2].iter().le([1, 2].iter()), true);

Run

### `pub fn gt<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,` 1.5.0[src]

Determines if the elements of this `Iterator` are lexicographically greater than those of another.

# Examples

    assert_eq!([1].iter().gt([1].iter()), false);
    assert_eq!([1].iter().gt([1, 2].iter()), false);
    assert_eq!([1, 2].iter().gt([1].iter()), true);
    assert_eq!([1, 2].iter().gt([1, 2].iter()), false);

Run

### `pub fn ge<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,` 1.5.0[src]

Determines if the elements of this `Iterator` are lexicographically greater than or equal to those of another.

# Examples

    assert_eq!([1].iter().ge([1].iter()), true);
    assert_eq!([1].iter().ge([1, 2].iter()), false);
    assert_eq!([1, 2].iter().ge([1].iter()), true);
    assert_eq!([1, 2].iter().ge([1, 2].iter()), true);

Run

### `pub fn is_sorted(self) -> bool where
Self::Item: PartialOrd<Self::Item>,` [src]

🔬 This is a nightly-only experimental API. (`is_sorted` #53485)

new API

Checks if the elements of this iterator are sorted.

That is, for each element `a` and its following element `b`, `a <= b` must hold. If the iterator yields exactly zero or one element, `true` is returned.

Note that if `Self::Item` is only `PartialOrd`, but not `Ord`, the above definition implies that this function returns `false` if any two consecutive items are not comparable.

# Examples

    #![feature(is_sorted)]

    assert!([1, 2, 2, 9].iter().is_sorted());
    assert!(![1, 3, 2, 4].iter().is_sorted());
    assert!([0].iter().is_sorted());
    assert!(std::iter::empty::<i32>().is_sorted());
    assert!(![0.0, 1.0, f32::NAN].iter().is_sorted());

Run

### `pub fn is_sorted_by<F>(self, compare: F) -> bool where
F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,` [src]

🔬 This is a nightly-only experimental API. (`is_sorted` #53485)

new API

Checks if the elements of this iterator are sorted using the given comparator function.

Instead of using `PartialOrd::partial_cmp`, this function uses the given `compare` function to determine the ordering of two elements. Apart from that, it's equivalent to `is_sorted`; see its documentation for more information.

# Examples

    #![feature(is_sorted)]

    assert!([1, 2, 2, 9].iter().is_sorted_by(|a, b| a.partial_cmp(b)));
    assert!(![1, 3, 2, 4].iter().is_sorted_by(|a, b| a.partial_cmp(b)));
    assert!([0].iter().is_sorted_by(|a, b| a.partial_cmp(b)));
    assert!(std::iter::empty::<i32>().is_sorted_by(|a, b| a.partial_cmp(b)));
    assert!(![0.0, 1.0, f32::NAN].iter().is_sorted_by(|a, b| a.partial_cmp(b)));

Run

### `pub fn is_sorted_by_key<F, K>(self, f: F) -> bool where
F: FnMut(Self::Item) -> K,
K: PartialOrd<K>,` [src]

🔬 This is a nightly-only experimental API. (`is_sorted` #53485)

new API

Checks if the elements of this iterator are sorted using the given key extraction function.

Instead of comparing the iterator's elements directly, this function compares the keys of the elements, as determined by `f`. Apart from that, it's equivalent to `is_sorted`; see its documentation for more information.

# Examples

    #![feature(is_sorted)]

    assert!(["c", "bb", "aaa"].iter().is_sorted_by_key(|s| s.len()));
    assert!(![-2i32, -1, 0, 3].iter().is_sorted_by_key(|n| n.abs()));

Run
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## Implementations on Foreign Types

### `impl<'a, T, P> Iterator for SplitInclusive<'a, T, P> where
P: FnMut(&T) -> bool,` [src]

#### `type Item = &'a [T]`

#### `pub fn next(&mut self) -> Option<&'a [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, T, P> Iterator for SplitInclusiveMut<'a, T, P> where
P: FnMut(&T) -> bool,` [src]

#### `type Item = &'a mut [T]`

#### `pub fn next(&mut self) -> Option<&'a mut [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a> Iterator for Utf8LossyChunksIter<'a>`[src]

#### `type Item = Utf8LossyChunk<'a>`

#### `pub fn next(&mut self) -> Option<Utf8LossyChunk<'a>>`[src]

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## Implementors

### `impl Iterator for std::ascii::EscapeDefault`[src]

#### `type Item = u8`

#### `pub fn next(&mut self) -> Option<u8>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn last(self) -> Option<u8>`[src]

### `impl Iterator for std::char::EscapeDebug`[src]

#### `type Item = char`

#### `pub fn next(&mut self) -> Option<char>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl Iterator for std::char::EscapeDefault`[src]

#### `type Item = char`

#### `pub fn next(&mut self) -> Option<char>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<char>`[src]

#### `pub fn last(self) -> Option<char>`[src]

### `impl Iterator for std::char::EscapeUnicode`[src]

#### `type Item = char`

#### `pub fn next(&mut self) -> Option<char>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn last(self) -> Option<char>`[src]

### `impl Iterator for ToLowercase`[src]

#### `type Item = char`

#### `pub fn next(&mut self) -> Option<char>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl Iterator for ToUppercase`[src]

#### `type Item = char`

#### `pub fn next(&mut self) -> Option<char>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl Iterator for Args`[src]

#### `type Item = String`

#### `pub fn next(&mut self) -> Option<String>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl Iterator for ArgsOs`[src]

#### `type Item = OsString`

#### `pub fn next(&mut self) -> Option<OsString>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl Iterator for Vars`[src]

#### `type Item = (String, String)`

#### `pub fn next(&mut self) -> Option<(String, String)>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl Iterator for VarsOs`[src]

#### `type Item = (OsString, OsString)`

#### `pub fn next(&mut self) -> Option<(OsString, OsString)>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl Iterator for ReadDir`[src]

#### `type Item = Result<DirEntry>`

#### `pub fn next(&mut self) -> Option<Result<DirEntry>>`[src]

### `impl<'_> Iterator for std::str::Bytes<'_>`[src]

#### `type Item = u8`

#### `pub fn next(&mut self) -> Option<u8>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn last(self) -> Option<<Bytes<'_> as Iterator>::Item>`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<<Bytes<'_> as Iterator>::Item>`[src]

#### `pub fn all<F>(&mut self, f: F) -> bool where
F: FnMut(<Bytes<'_> as Iterator>::Item) -> bool,` [src]

#### `pub fn any<F>(&mut self, f: F) -> bool where
F: FnMut(<Bytes<'_> as Iterator>::Item) -> bool,` [src]

#### `pub fn find<P>(&mut self, predicate: P) -> Option<<Bytes<'_> as Iterator>::Item> where
P: FnMut(&<Bytes<'_> as Iterator>::Item) -> bool,` [src]

#### `pub fn position<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(<Bytes<'_> as Iterator>::Item) -> bool,` [src]

#### `pub fn rposition<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(<Bytes<'_> as Iterator>::Item) -> bool,` [src]

#### `pub unsafe fn __iterator_get_unchecked(&mut self, idx: usize) -> u8`[src]

### `impl<'_> Iterator for std::string::Drain<'_>`[src]

#### `type Item = char`

#### `pub fn next(&mut self) -> Option<char>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn last(self) -> Option<char>`[src]

### `impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized,` [src]

#### `type Item = <I as Iterator>::Item`

#### `pub fn next(&mut self) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn advance_by(&mut self, n: usize) -> Result<(), usize>`[src]

🔬 This is a nightly-only experimental API. (`iter_advance_by` #77404)

recently added

#### `pub fn nth(&mut self, n: usize) -> Option<<&'_ mut I as Iterator>::Item>`[src]

### `impl<'_, I, A> Iterator for Splice<'_, I, A> where
A: Allocator,
I: Iterator,` [src]

#### `type Item = <I as Iterator>::Item`

#### `pub fn next(&mut self) -> Option<<Splice<'_, I, A> as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'_, K, V, F> Iterator for std::collections::btree_map::DrainFilter<'_, K, V, F> where
F: FnMut(&K, &mut V) -> bool,` [src]

#### `type Item = (K, V)`

#### `pub fn next(&mut self) -> Option<(K, V)>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'_, T> Iterator for std::collections::binary_heap::Drain<'_, T>`[src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'_, T> Iterator for DrainSorted<'_, T> where
T: Ord,` [src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'_, T> Iterator for std::collections::vec_deque::Drain<'_, T>`[src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'_, T, A> Iterator for std::vec::Drain<'_, T, A> where
A: Allocator,` [src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'_, T, F> Iterator for std::collections::linked_list::DrainFilter<'_, T, F> where
F: FnMut(&mut T) -> bool,` [src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'_, T, F, A> Iterator for std::vec::DrainFilter<'_, T, F, A> where
A: Allocator,
F: FnMut(&mut T) -> bool,` [src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a> Iterator for SplitPaths<'a>`[src]

#### `type Item = PathBuf`

#### `pub fn next(&mut self) -> Option<PathBuf>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a> Iterator for std::error::Chain<'a>`[src]

#### `type Item = &'a (dyn Error + 'static)`

#### `pub fn next(&mut self) -> Option<Self::Item>`[src]

### `impl<'a> Iterator for std::net::Incoming<'a>`[src]

#### `type Item = Result<TcpStream>`

#### `pub fn next(&mut self) -> Option<Result<TcpStream>>`[src]

### `impl<'a> Iterator for std::os::unix::net::Incoming<'a>`[src]

#### `type Item = Result<UnixStream>`

#### `pub fn next(&mut self) -> Option<Result<UnixStream>>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a> Iterator for Messages<'a>`[src]

#### `type Item = Result<AncillaryData<'a>, AncillaryError>`

#### `pub fn next(&mut self) -> Option<Self::Item>`[src]

### `impl<'a> Iterator for ScmCredentials<'a>`[src]

#### `type Item = SocketCred`

#### `pub fn next(&mut self) -> Option<SocketCred>`[src]

### `impl<'a> Iterator for ScmRights<'a>`[src]

#### `type Item = RawFd`

#### `pub fn next(&mut self) -> Option<RawFd>`[src]

### `impl<'a> Iterator for EncodeWide<'a>`[src]

#### `type Item = u16`

#### `pub fn next(&mut self) -> Option<u16>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a> Iterator for Ancestors<'a>`[src]

#### `type Item = &'a Path`

#### `pub fn next(&mut self) -> Option<Self::Item>`[src]

### `impl<'a> Iterator for Components<'a>`[src]

#### `type Item = Component<'a>`

#### `pub fn next(&mut self) -> Option<Component<'a>>`[src]

### `impl<'a> Iterator for std::path::Iter<'a>`[src]

#### `type Item = &'a OsStr`

#### `pub fn next(&mut self) -> Option<&'a OsStr>`[src]

### `impl<'a> Iterator for CommandArgs<'a>`[src]

#### `type Item = &'a OsStr`

#### `pub fn next(&mut self) -> Option<&'a OsStr>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a> Iterator for CommandEnvs<'a>`[src]

#### `type Item = (&'a OsStr, Option<&'a OsStr>)`

#### `pub fn next(&mut self) -> Option<Self::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a> Iterator for CharIndices<'a>`[src]

#### `type Item = (usize, char)`

#### `pub fn next(&mut self) -> Option<(usize, char)>`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn last(self) -> Option<(usize, char)>`[src]

### `impl<'a> Iterator for Chars<'a>`[src]

#### `type Item = char`

#### `pub fn next(&mut self) -> Option<char>`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn last(self) -> Option<char>`[src]

### `impl<'a> Iterator for EncodeUtf16<'a>`[src]

#### `type Item = u16`

#### `pub fn next(&mut self) -> Option<u16>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a> Iterator for std::str::EscapeDebug<'a>`[src]

#### `type Item = char`

#### `pub fn next(&mut self) -> Option<char>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <EscapeDebug<'a> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
EscapeDebug<'a>: Sized,` [src]

#### `pub fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <EscapeDebug<'a> as Iterator>::Item) -> Acc,` [src]

### `impl<'a> Iterator for std::str::EscapeDefault<'a>`[src]

#### `type Item = char`

#### `pub fn next(&mut self) -> Option<char>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <EscapeDefault<'a> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
EscapeDefault<'a>: Sized,` [src]

#### `pub fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <EscapeDefault<'a> as Iterator>::Item) -> Acc,` [src]

### `impl<'a> Iterator for std::str::EscapeUnicode<'a>`[src]

#### `type Item = char`

#### `pub fn next(&mut self) -> Option<char>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <EscapeUnicode<'a> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
EscapeUnicode<'a>: Sized,` [src]

#### `pub fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <EscapeUnicode<'a> as Iterator>::Item) -> Acc,` [src]

### `impl<'a> Iterator for std::str::Lines<'a>`[src]

#### `type Item = &'a str`

#### `pub fn next(&mut self) -> Option<&'a str>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn last(self) -> Option<&'a str>`[src]

### `impl<'a> Iterator for LinesAny<'a>`[src]

#### `type Item = &'a str`

#### `pub fn next(&mut self) -> Option<&'a str>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a> Iterator for SplitAsciiWhitespace<'a>`[src]

#### `type Item = &'a str`

#### `pub fn next(&mut self) -> Option<&'a str>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn last(self) -> Option<&'a str>`[src]

### `impl<'a> Iterator for SplitWhitespace<'a>`[src]

#### `type Item = &'a str`

#### `pub fn next(&mut self) -> Option<&'a str>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn last(self) -> Option<&'a str>`[src]

### `impl<'a, '_, T, F> Iterator for std::collections::btree_set::DrainFilter<'_, T, F> where
F: 'a + FnMut(&T) -> bool,` [src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, A> Iterator for std::option::Iter<'a, A>`[src]

#### `type Item = &'a A`

#### `pub fn next(&mut self) -> Option<&'a A>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, A> Iterator for std::option::IterMut<'a, A>`[src]

#### `type Item = &'a mut A`

#### `pub fn next(&mut self) -> Option<&'a mut A>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, I, T> Iterator for Cloned<I> where
I: Iterator<Item = &'a T>,
T: 'a + Clone,` [src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
F: FnMut(B, <Cloned<I> as Iterator>::Item) -> R,
R: Try<Ok = B>,
Cloned<I>: Sized,` [src]

#### `pub fn fold<Acc, F>(self, init: Acc, f: F) -> Acc where
F: FnMut(Acc, <Cloned<I> as Iterator>::Item) -> Acc,` [src]

#### `pub unsafe fn __iterator_get_unchecked(&mut self, idx: usize) -> T where
Cloned<I>: TrustedRandomAccess,` [src]

### `impl<'a, I, T> Iterator for Copied<I> where
I: Iterator<Item = &'a T>,
T: 'a + Copy,` [src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
F: FnMut(B, <Copied<I> as Iterator>::Item) -> R,
R: Try<Ok = B>,
Copied<I>: Sized,` [src]

#### `pub fn fold<Acc, F>(self, init: Acc, f: F) -> Acc where
F: FnMut(Acc, <Copied<I> as Iterator>::Item) -> Acc,` [src]

#### `pub fn nth(&mut self, n: usize) -> Option<T>`[src]

#### `pub fn last(self) -> Option<T>`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub unsafe fn __iterator_get_unchecked(&mut self, idx: usize) -> T where
Copied<I>: TrustedRandomAccess,` [src]

### `impl<'a, K> Iterator for std::collections::hash_set::Drain<'a, K>`[src]

#### `type Item = K`

#### `pub fn next(&mut self) -> Option<K>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, K> Iterator for std::collections::hash_set::Iter<'a, K>`[src]

#### `type Item = &'a K`

#### `pub fn next(&mut self) -> Option<&'a K>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, K, V> Iterator for std::collections::btree_map::Iter<'a, K, V> where
K: 'a,
V: 'a,` [src]

#### `type Item = (&'a K, &'a V)`

#### `pub fn next(&mut self) -> Option<(&'a K, &'a V)>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn last(self) -> Option<(&'a K, &'a V)>`[src]

#### `pub fn min(self) -> Option<(&'a K, &'a V)>`[src]

#### `pub fn max(self) -> Option<(&'a K, &'a V)>`[src]

### `impl<'a, K, V> Iterator for std::collections::btree_map::IterMut<'a, K, V> where
K: 'a,
V: 'a,` [src]

#### `type Item = (&'a K, &'a mut V)`

#### `pub fn next(&mut self) -> Option<(&'a K, &'a mut V)>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn last(self) -> Option<(&'a K, &'a mut V)>`[src]

#### `pub fn min(self) -> Option<(&'a K, &'a mut V)>`[src]

#### `pub fn max(self) -> Option<(&'a K, &'a mut V)>`[src]

### `impl<'a, K, V> Iterator for std::collections::btree_map::Keys<'a, K, V>`[src]

#### `type Item = &'a K`

#### `pub fn next(&mut self) -> Option<&'a K>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn last(self) -> Option<&'a K>`[src]

#### `pub fn min(self) -> Option<&'a K>`[src]

#### `pub fn max(self) -> Option<&'a K>`[src]

### `impl<'a, K, V> Iterator for std::collections::btree_map::Range<'a, K, V>`[src]

#### `type Item = (&'a K, &'a V)`

#### `pub fn next(&mut self) -> Option<(&'a K, &'a V)>`[src]

#### `pub fn last(self) -> Option<(&'a K, &'a V)>`[src]

#### `pub fn min(self) -> Option<(&'a K, &'a V)>`[src]

#### `pub fn max(self) -> Option<(&'a K, &'a V)>`[src]

### `impl<'a, K, V> Iterator for RangeMut<'a, K, V>`[src]

#### `type Item = (&'a K, &'a mut V)`

#### `pub fn next(&mut self) -> Option<(&'a K, &'a mut V)>`[src]

#### `pub fn last(self) -> Option<(&'a K, &'a mut V)>`[src]

#### `pub fn min(self) -> Option<(&'a K, &'a mut V)>`[src]

#### `pub fn max(self) -> Option<(&'a K, &'a mut V)>`[src]

### `impl<'a, K, V> Iterator for std::collections::btree_map::Values<'a, K, V>`[src]

#### `type Item = &'a V`

#### `pub fn next(&mut self) -> Option<&'a V>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn last(self) -> Option<&'a V>`[src]

### `impl<'a, K, V> Iterator for std::collections::btree_map::ValuesMut<'a, K, V>`[src]

#### `type Item = &'a mut V`

#### `pub fn next(&mut self) -> Option<&'a mut V>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn last(self) -> Option<&'a mut V>`[src]

### `impl<'a, K, V> Iterator for std::collections::hash_map::Drain<'a, K, V>`[src]

#### `type Item = (K, V)`

#### `pub fn next(&mut self) -> Option<(K, V)>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, K, V> Iterator for std::collections::hash_map::Iter<'a, K, V>`[src]

#### `type Item = (&'a K, &'a V)`

#### `pub fn next(&mut self) -> Option<(&'a K, &'a V)>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, K, V> Iterator for std::collections::hash_map::IterMut<'a, K, V>`[src]

#### `type Item = (&'a K, &'a mut V)`

#### `pub fn next(&mut self) -> Option<(&'a K, &'a mut V)>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, K, V> Iterator for std::collections::hash_map::Keys<'a, K, V>`[src]

#### `type Item = &'a K`

#### `pub fn next(&mut self) -> Option<&'a K>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, K, V> Iterator for std::collections::hash_map::Values<'a, K, V>`[src]

#### `type Item = &'a V`

#### `pub fn next(&mut self) -> Option<&'a V>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, K, V> Iterator for std::collections::hash_map::ValuesMut<'a, K, V>`[src]

#### `type Item = &'a mut V`

#### `pub fn next(&mut self) -> Option<&'a mut V>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, P> Iterator for MatchIndices<'a, P> where
P: Pattern<'a>,` [src]

#### `type Item = (usize, &'a str)`

#### `pub fn next(&mut self) -> Option<(usize, &'a str)>`[src]

### `impl<'a, P> Iterator for Matches<'a, P> where
P: Pattern<'a>,` [src]

#### `type Item = &'a str`

#### `pub fn next(&mut self) -> Option<&'a str>`[src]

### `impl<'a, P> Iterator for RMatchIndices<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,` [src]

#### `type Item = (usize, &'a str)`

#### `pub fn next(&mut self) -> Option<(usize, &'a str)>`[src]

### `impl<'a, P> Iterator for RMatches<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,` [src]

#### `type Item = &'a str`

#### `pub fn next(&mut self) -> Option<&'a str>`[src]

### `impl<'a, P> Iterator for std::str::RSplit<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,` [src]

#### `type Item = &'a str`

#### `pub fn next(&mut self) -> Option<&'a str>`[src]

### `impl<'a, P> Iterator for std::str::RSplitN<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,` [src]

#### `type Item = &'a str`

#### `pub fn next(&mut self) -> Option<&'a str>`[src]

### `impl<'a, P> Iterator for RSplitTerminator<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,` [src]

#### `type Item = &'a str`

#### `pub fn next(&mut self) -> Option<&'a str>`[src]

### `impl<'a, P> Iterator for std::str::Split<'a, P> where
P: Pattern<'a>,` [src]

#### `type Item = &'a str`

#### `pub fn next(&mut self) -> Option<&'a str>`[src]

### `impl<'a, P> Iterator for std::str::SplitN<'a, P> where
P: Pattern<'a>,` [src]

#### `type Item = &'a str`

#### `pub fn next(&mut self) -> Option<&'a str>`[src]

### `impl<'a, P> Iterator for SplitTerminator<'a, P> where
P: Pattern<'a>,` [src]

#### `type Item = &'a str`

#### `pub fn next(&mut self) -> Option<&'a str>`[src]

### `impl<'a, T> Iterator for std::collections::binary_heap::Iter<'a, T>`[src]

#### `type Item = &'a T`

#### `pub fn next(&mut self) -> Option<&'a T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn last(self) -> Option<&'a T>`[src]

### `impl<'a, T> Iterator for std::collections::btree_set::Difference<'a, T> where
T: Ord,` [src]

#### `type Item = &'a T`

#### `pub fn next(&mut self) -> Option<&'a T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn min(self) -> Option<&'a T>`[src]

### `impl<'a, T> Iterator for std::collections::btree_set::Intersection<'a, T> where
T: Ord,` [src]

#### `type Item = &'a T`

#### `pub fn next(&mut self) -> Option<&'a T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn min(self) -> Option<&'a T>`[src]

### `impl<'a, T> Iterator for std::collections::btree_set::Iter<'a, T>`[src]

#### `type Item = &'a T`

#### `pub fn next(&mut self) -> Option<&'a T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn last(self) -> Option<&'a T>`[src]

#### `pub fn min(self) -> Option<&'a T>`[src]

#### `pub fn max(self) -> Option<&'a T>`[src]

### `impl<'a, T> Iterator for std::collections::btree_set::Range<'a, T>`[src]

#### `type Item = &'a T`

#### `pub fn next(&mut self) -> Option<&'a T>`[src]

#### `pub fn last(self) -> Option<&'a T>`[src]

#### `pub fn min(self) -> Option<&'a T>`[src]

#### `pub fn max(self) -> Option<&'a T>`[src]

### `impl<'a, T> Iterator for std::collections::btree_set::SymmetricDifference<'a, T> where
T: Ord,` [src]

#### `type Item = &'a T`

#### `pub fn next(&mut self) -> Option<&'a T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn min(self) -> Option<&'a T>`[src]

### `impl<'a, T> Iterator for std::collections::btree_set::Union<'a, T> where
T: Ord,` [src]

#### `type Item = &'a T`

#### `pub fn next(&mut self) -> Option<&'a T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn min(self) -> Option<&'a T>`[src]

### `impl<'a, T> Iterator for std::collections::linked_list::Iter<'a, T>`[src]

#### `type Item = &'a T`

#### `pub fn next(&mut self) -> Option<&'a T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn last(self) -> Option<&'a T>`[src]

### `impl<'a, T> Iterator for std::collections::linked_list::IterMut<'a, T>`[src]

#### `type Item = &'a mut T`

#### `pub fn next(&mut self) -> Option<&'a mut T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn last(self) -> Option<&'a mut T>`[src]

### `impl<'a, T> Iterator for std::collections::vec_deque::Iter<'a, T>`[src]

#### `type Item = &'a T`

#### `pub fn next(&mut self) -> Option<&'a T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn fold<Acc, F>(self, accum: Acc, f: F) -> Acc where
F: FnMut(Acc, <Iter<'a, T> as Iterator>::Item) -> Acc,` [src]

#### `pub fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
F: FnMut(B, <Iter<'a, T> as Iterator>::Item) -> R,
R: Try<Ok = B>,
Iter<'a, T>: Sized,` [src]

#### `pub fn nth(&mut self, n: usize) -> Option<<Iter<'a, T> as Iterator>::Item>`[src]

#### `pub fn last(self) -> Option<&'a T>`[src]

### `impl<'a, T> Iterator for std::collections::vec_deque::IterMut<'a, T>`[src]

#### `type Item = &'a mut T`

#### `pub fn next(&mut self) -> Option<&'a mut T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn fold<Acc, F>(self, accum: Acc, f: F) -> Acc where
F: FnMut(Acc, <IterMut<'a, T> as Iterator>::Item) -> Acc,` [src]

#### `pub fn nth(&mut self, n: usize) -> Option<<IterMut<'a, T> as Iterator>::Item>`[src]

#### `pub fn last(self) -> Option<&'a mut T>`[src]

### `impl<'a, T> Iterator for std::result::Iter<'a, T>`[src]

#### `type Item = &'a T`

#### `pub fn next(&mut self) -> Option<&'a T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, T> Iterator for std::result::IterMut<'a, T>`[src]

#### `type Item = &'a mut T`

#### `pub fn next(&mut self) -> Option<&'a mut T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, T> Iterator for Chunks<'a, T>`[src]

#### `type Item = &'a [T]`

#### `pub fn next(&mut self) -> Option<&'a [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<<Chunks<'a, T> as Iterator>::Item>`[src]

#### `pub fn last(self) -> Option<<Chunks<'a, T> as Iterator>::Item>`[src]

### `impl<'a, T> Iterator for ChunksExact<'a, T>`[src]

#### `type Item = &'a [T]`

#### `pub fn next(&mut self) -> Option<&'a [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn nth(
&mut self,
n: usize
) -> Option<<ChunksExact<'a, T> as Iterator>::Item>`[src]

#### `pub fn last(self) -> Option<<ChunksExact<'a, T> as Iterator>::Item>`[src]

### `impl<'a, T> Iterator for ChunksExactMut<'a, T>`[src]

#### `type Item = &'a mut [T]`

#### `pub fn next(&mut self) -> Option<&'a mut [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<&'a mut [T]>`[src]

#### `pub fn last(self) -> Option<<ChunksExactMut<'a, T> as Iterator>::Item>`[src]

### `impl<'a, T> Iterator for ChunksMut<'a, T>`[src]

#### `type Item = &'a mut [T]`

#### `pub fn next(&mut self) -> Option<&'a mut [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<&'a mut [T]>`[src]

#### `pub fn last(self) -> Option<<ChunksMut<'a, T> as Iterator>::Item>`[src]

### `impl<'a, T> Iterator for std::slice::Iter<'a, T>`[src]

#### `type Item = &'a T`

#### `pub fn next(&mut self) -> Option<&'a T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<&'a T>`[src]

#### `pub fn last(self) -> Option<&'a T>`[src]

#### `pub fn for_each<F>(self, f: F) where
F: FnMut(<Iter<'a, T> as Iterator>::Item),
Iter<'a, T>: Sized,` [src]

#### `pub fn all<F>(&mut self, f: F) -> bool where
F: FnMut(<Iter<'a, T> as Iterator>::Item) -> bool,
Iter<'a, T>: Sized,` [src]

#### `pub fn any<F>(&mut self, f: F) -> bool where
F: FnMut(<Iter<'a, T> as Iterator>::Item) -> bool,
Iter<'a, T>: Sized,` [src]

#### `pub fn find<P>(
&mut self,
predicate: P
) -> Option<<Iter<'a, T> as Iterator>::Item> where
P: FnMut(&<Iter<'a, T> as Iterator>::Item) -> bool,
Iter<'a, T>: Sized,` [src]

#### `pub fn find_map<B, F>(&mut self, f: F) -> Option<B> where
F: FnMut(<Iter<'a, T> as Iterator>::Item) -> Option<B>,
Iter<'a, T>: Sized,` [src]

#### `pub fn position<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(<Iter<'a, T> as Iterator>::Item) -> bool,
Iter<'a, T>: Sized,` [src]

#### `pub fn rposition<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(<Iter<'a, T> as Iterator>::Item) -> bool,
Iter<'a, T>: Sized,
Iter<'a, T>: ExactSizeIterator,
Iter<'a, T>: DoubleEndedIterator,` [src]

#### `pub fn is_sorted_by<F>(self, compare: F) -> bool where
F: FnMut(&<Iter<'a, T> as Iterator>::Item, &<Iter<'a, T> as Iterator>::Item) -> Option<Ordering>,
Iter<'a, T>: Sized,` [src]

🔬 This is a nightly-only experimental API. (`is_sorted` #53485)

new API

### `impl<'a, T> Iterator for std::slice::IterMut<'a, T>`[src]

#### `type Item = &'a mut T`

#### `pub fn next(&mut self) -> Option<&'a mut T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<&'a mut T>`[src]

#### `pub fn last(self) -> Option<&'a mut T>`[src]

#### `pub fn for_each<F>(self, f: F) where
F: FnMut(<IterMut<'a, T> as Iterator>::Item),
IterMut<'a, T>: Sized,` [src]

#### `pub fn all<F>(&mut self, f: F) -> bool where
F: FnMut(<IterMut<'a, T> as Iterator>::Item) -> bool,
IterMut<'a, T>: Sized,` [src]

#### `pub fn any<F>(&mut self, f: F) -> bool where
F: FnMut(<IterMut<'a, T> as Iterator>::Item) -> bool,
IterMut<'a, T>: Sized,` [src]

#### `pub fn find<P>(
&mut self,
predicate: P
) -> Option<<IterMut<'a, T> as Iterator>::Item> where
P: FnMut(&<IterMut<'a, T> as Iterator>::Item) -> bool,
IterMut<'a, T>: Sized,` [src]

#### `pub fn find_map<B, F>(&mut self, f: F) -> Option<B> where
F: FnMut(<IterMut<'a, T> as Iterator>::Item) -> Option<B>,
IterMut<'a, T>: Sized,` [src]

#### `pub fn position<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(<IterMut<'a, T> as Iterator>::Item) -> bool,
IterMut<'a, T>: Sized,` [src]

#### `pub fn rposition<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(<IterMut<'a, T> as Iterator>::Item) -> bool,
IterMut<'a, T>: Sized,
IterMut<'a, T>: ExactSizeIterator,
IterMut<'a, T>: DoubleEndedIterator,` [src]

### `impl<'a, T> Iterator for RChunks<'a, T>`[src]

#### `type Item = &'a [T]`

#### `pub fn next(&mut self) -> Option<&'a [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<<RChunks<'a, T> as Iterator>::Item>`[src]

#### `pub fn last(self) -> Option<<RChunks<'a, T> as Iterator>::Item>`[src]

### `impl<'a, T> Iterator for RChunksExact<'a, T>`[src]

#### `type Item = &'a [T]`

#### `pub fn next(&mut self) -> Option<&'a [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn nth(
&mut self,
n: usize
) -> Option<<RChunksExact<'a, T> as Iterator>::Item>`[src]

#### `pub fn last(self) -> Option<<RChunksExact<'a, T> as Iterator>::Item>`[src]

### `impl<'a, T> Iterator for RChunksExactMut<'a, T>`[src]

#### `type Item = &'a mut [T]`

#### `pub fn next(&mut self) -> Option<&'a mut [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<&'a mut [T]>`[src]

#### `pub fn last(self) -> Option<<RChunksExactMut<'a, T> as Iterator>::Item>`[src]

### `impl<'a, T> Iterator for RChunksMut<'a, T>`[src]

#### `type Item = &'a mut [T]`

#### `pub fn next(&mut self) -> Option<&'a mut [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<&'a mut [T]>`[src]

#### `pub fn last(self) -> Option<<RChunksMut<'a, T> as Iterator>::Item>`[src]

### `impl<'a, T> Iterator for Windows<'a, T>`[src]

#### `type Item = &'a [T]`

#### `pub fn next(&mut self) -> Option<&'a [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<<Windows<'a, T> as Iterator>::Item>`[src]

#### `pub fn last(self) -> Option<<Windows<'a, T> as Iterator>::Item>`[src]

### `impl<'a, T> Iterator for std::sync::mpsc::Iter<'a, T>`[src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

### `impl<'a, T> Iterator for TryIter<'a, T>`[src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

### `impl<'a, T, P> Iterator for std::slice::RSplit<'a, T, P> where
P: FnMut(&T) -> bool,` [src]

#### `type Item = &'a [T]`

#### `pub fn next(&mut self) -> Option<&'a [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, T, P> Iterator for RSplitMut<'a, T, P> where
P: FnMut(&T) -> bool,` [src]

#### `type Item = &'a mut [T]`

#### `pub fn next(&mut self) -> Option<&'a mut [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, T, P> Iterator for std::slice::RSplitN<'a, T, P> where
P: FnMut(&T) -> bool,` [src]

#### `type Item = &'a [T]`

#### `pub fn next(&mut self) -> Option<&'a [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, T, P> Iterator for RSplitNMut<'a, T, P> where
P: FnMut(&T) -> bool,` [src]

#### `type Item = &'a mut [T]`

#### `pub fn next(&mut self) -> Option<&'a mut [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, T, P> Iterator for std::slice::Split<'a, T, P> where
P: FnMut(&T) -> bool,` [src]

#### `type Item = &'a [T]`

#### `pub fn next(&mut self) -> Option<&'a [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, T, P> Iterator for SplitMut<'a, T, P> where
P: FnMut(&T) -> bool,` [src]

#### `type Item = &'a mut [T]`

#### `pub fn next(&mut self) -> Option<&'a mut [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, T, P> Iterator for std::slice::SplitN<'a, T, P> where
P: FnMut(&T) -> bool,` [src]

#### `type Item = &'a [T]`

#### `pub fn next(&mut self) -> Option<&'a [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, T, P> Iterator for SplitNMut<'a, T, P> where
P: FnMut(&T) -> bool,` [src]

#### `type Item = &'a mut [T]`

#### `pub fn next(&mut self) -> Option<&'a mut [T]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, T, S> Iterator for std::collections::hash_set::Difference<'a, T, S> where
T: Eq + Hash,
S: BuildHasher,` [src]

#### `type Item = &'a T`

#### `pub fn next(&mut self) -> Option<&'a T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, T, S> Iterator for std::collections::hash_set::Intersection<'a, T, S> where
T: Eq + Hash,
S: BuildHasher,` [src]

#### `type Item = &'a T`

#### `pub fn next(&mut self) -> Option<&'a T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, T, S> Iterator for std::collections::hash_set::SymmetricDifference<'a, T, S> where
T: Eq + Hash,
S: BuildHasher,` [src]

#### `type Item = &'a T`

#### `pub fn next(&mut self) -> Option<&'a T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, T, S> Iterator for std::collections::hash_set::Union<'a, T, S> where
T: Eq + Hash,
S: BuildHasher,` [src]

#### `type Item = &'a T`

#### `pub fn next(&mut self) -> Option<&'a T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<'a, T, const N: usize> Iterator for ArrayChunks<'a, T, N>`[src]

#### `type Item = &'a [T; N]`

#### `pub fn next(&mut self) -> Option<&'a [T; N]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn nth(
&mut self,
n: usize
) -> Option<<ArrayChunks<'a, T, N> as Iterator>::Item>`[src]

#### `pub fn last(self) -> Option<<ArrayChunks<'a, T, N> as Iterator>::Item>`[src]

#### `pub unsafe fn __iterator_get_unchecked(&mut self, i: usize) -> &'a [T; N]`[src]

### `impl<'a, T, const N: usize> Iterator for ArrayChunksMut<'a, T, N>`[src]

#### `type Item = &'a mut [T; N]`

#### `pub fn next(&mut self) -> Option<&'a mut [T; N]>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn nth(
&mut self,
n: usize
) -> Option<<ArrayChunksMut<'a, T, N> as Iterator>::Item>`[src]

#### `pub fn last(self) -> Option<<ArrayChunksMut<'a, T, N> as Iterator>::Item>`[src]

#### `pub unsafe fn __iterator_get_unchecked(&mut self, i: usize) -> &'a mut [T; N]`[src]

### `impl<'a, T, const N: usize> Iterator for ArrayWindows<'a, T, N>`[src]

#### `type Item = &'a [T; N]`

#### `pub fn next(&mut self) -> Option<<ArrayWindows<'a, T, N> as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn nth(
&mut self,
n: usize
) -> Option<<ArrayWindows<'a, T, N> as Iterator>::Item>`[src]

#### `pub fn last(self) -> Option<<ArrayWindows<'a, T, N> as Iterator>::Item>`[src]

### `impl<A> Iterator for Repeat<A> where
A: Clone,` [src]

#### `type Item = A`

#### `pub fn next(&mut self) -> Option<A>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<A> Iterator for std::ops::Range<A> where
A: Step,` [src]

#### `type Item = A`

#### `pub fn next(&mut self) -> Option<A>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<A>`[src]

#### `pub fn last(self) -> Option<A>`[src]

#### `pub fn min(self) -> Option<A>`[src]

#### `pub fn max(self) -> Option<A>`[src]

### `impl<A> Iterator for RangeFrom<A> where
A: Step,` [src]

#### `type Item = A`

#### `pub fn next(&mut self) -> Option<A>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<A>`[src]

### `impl<A> Iterator for RangeInclusive<A> where
A: Step,` [src]

#### `type Item = A`

#### `pub fn next(&mut self) -> Option<A>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<A>`[src]

#### `pub fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
F: FnMut(B, <RangeInclusive<A> as Iterator>::Item) -> R,
R: Try<Ok = B>,
RangeInclusive<A>: Sized,` [src]

#### `pub fn fold<B, F>(self, init: B, f: F) -> B where
F: FnMut(B, <RangeInclusive<A> as Iterator>::Item) -> B,
RangeInclusive<A>: Sized,` [src]

#### `pub fn last(self) -> Option<A>`[src]

#### `pub fn min(self) -> Option<A>`[src]

#### `pub fn max(self) -> Option<A>`[src]

### `impl<A> Iterator for std::option::IntoIter<A>`[src]

#### `type Item = A`

#### `pub fn next(&mut self) -> Option<A>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<A, B> Iterator for std::iter::Chain<A, B> where
A: Iterator,
B: Iterator<Item = <A as Iterator>::Item>,` [src]

#### `type Item = <A as Iterator>::Item`

#### `pub fn next(&mut self) -> Option<<A as Iterator>::Item>`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn try_fold<Acc, F, R>(&mut self, acc: Acc, f: F) -> R where
F: FnMut(Acc, <Chain<A, B> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Chain<A, B>: Sized,` [src]

#### `pub fn fold<Acc, F>(self, acc: Acc, f: F) -> Acc where
F: FnMut(Acc, <Chain<A, B> as Iterator>::Item) -> Acc,` [src]

#### `pub fn advance_by(&mut self, n: usize) -> Result<(), usize>`[src]

🔬 This is a nightly-only experimental API. (`iter_advance_by` #77404)

recently added

#### `pub fn nth(&mut self, n: usize) -> Option<<Chain<A, B> as Iterator>::Item>`[src]

#### `pub fn find<P>(
&mut self,
predicate: P
) -> Option<<Chain<A, B> as Iterator>::Item> where
P: FnMut(&<Chain<A, B> as Iterator>::Item) -> bool,` [src]

#### `pub fn last(self) -> Option<<A as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<A, B> Iterator for Zip<A, B> where
A: Iterator,
B: Iterator,` [src]

#### `type Item = (<A as Iterator>::Item, <B as Iterator>::Item)`

#### `pub fn next(&mut self) -> Option<<Zip<A, B> as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<<Zip<A, B> as Iterator>::Item>`[src]

#### `pub unsafe fn __iterator_get_unchecked(
&mut self,
idx: usize
) -> <Zip<A, B> as Iterator>::Itemⓘ

### Notable traits for Zip<A, B>

`impl<A, B> Iterator for Zip<A, B> where
A: Iterator,
B: Iterator, type Item = (<A as Iterator>::Item, <B as Iterator>::Item);`
where
Zip<A, B>: TrustedRandomAccess,` [src]

### `impl<A, F> Iterator for OnceWith<F> where
F: FnOnce() -> A,` [src]

#### `type Item = A`

#### `pub fn next(&mut self) -> Option<A>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<A, F> Iterator for RepeatWith<F> where
F: FnMut() -> A,` [src]

#### `type Item = A`

#### `pub fn next(&mut self) -> Option<A>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<B, I, F> Iterator for FilterMap<I, F> where
F: FnMut(<I as Iterator>::Item) -> Option<B>,
I: Iterator,` [src]

#### `type Item = B`

#### `pub fn next(&mut self) -> Option<B>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <FilterMap<I, F> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
FilterMap<I, F>: Sized,` [src]

#### `pub fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <FilterMap<I, F> as Iterator>::Item) -> Acc,` [src]

### `impl<B, I, F> Iterator for Map<I, F> where
F: FnMut(<I as Iterator>::Item) -> B,
I: Iterator,` [src]

#### `type Item = B`

#### `pub fn next(&mut self) -> Option<B>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<Acc, G, R>(&mut self, init: Acc, g: G) -> R where
G: FnMut(Acc, <Map<I, F> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Map<I, F>: Sized,` [src]

#### `pub fn fold<Acc, G>(self, init: Acc, g: G) -> Acc where
G: FnMut(Acc, <Map<I, F> as Iterator>::Item) -> Acc,` [src]

#### `pub unsafe fn __iterator_get_unchecked(&mut self, idx: usize) -> B where
Map<I, F>: TrustedRandomAccess,` [src]

### `impl<B, I, P> Iterator for MapWhile<I, P> where
I: Iterator,
P: FnMut(<I as Iterator>::Item) -> Option<B>,` [src]

#### `type Item = B`

#### `pub fn next(&mut self) -> Option<B>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <MapWhile<I, P> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
MapWhile<I, P>: Sized,` [src]

#### `pub fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <MapWhile<I, P> as Iterator>::Item) -> Acc,
MapWhile<I, P>: Sized,` [src]

### `impl<B, I, St, F> Iterator for Scan<I, St, F> where
F: FnMut(&mut St, <I as Iterator>::Item) -> Option<B>,
I: Iterator,` [src]

#### `type Item = B`

#### `pub fn next(&mut self) -> Option<B>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <Scan<I, St, F> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Scan<I, St, F>: Sized,` [src]

#### `pub fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <Scan<I, St, F> as Iterator>::Item) -> Acc,
Scan<I, St, F>: Sized,` [src]

### `impl<B: BufRead> Iterator for std::io::Lines<B>`[src]

#### `type Item = Result<String>`

#### `pub fn next(&mut self) -> Option<Result<String>>`[src]

### `impl<B: BufRead> Iterator for std::io::Split<B>`[src]

#### `type Item = Result<Vec<u8>>`

#### `pub fn next(&mut self) -> Option<Result<Vec<u8>>>`[src]

### `impl<I> Iterator for DecodeUtf16<I> where
I: Iterator<Item = u16>,` [src]

#### `type Item = Result<char, DecodeUtf16Error>`

#### `pub fn next(&mut self) -> Option<Result<char, DecodeUtf16Error>>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<I> Iterator for Cycle<I> where
I: Clone + Iterator,` [src]

#### `type Item = <I as Iterator>::Item`

#### `pub fn next(&mut self) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<Acc, F, R>(&mut self, acc: Acc, f: F) -> R where
F: FnMut(Acc, <Cycle<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,` [src]

### `impl<I> Iterator for Enumerate<I> where
I: Iterator,` [src]

#### `type Item = (usize, <I as Iterator>::Item)`

#### `pub fn next(&mut self) -> Option<(usize, <I as Iterator>::Item)>`[src]

# Overflow Behavior

The method does no guarding against overflows, so enumerating more than `usize::MAX` elements either produces the wrong result or panics. If debug assertions are enabled, a panic is guaranteed.

# Panics

Might panic if the index of the element overflows a `usize`.

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<(usize, <I as Iterator>::Item)>`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <Enumerate<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Enumerate<I>: Sized,` [src]

#### `pub fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <Enumerate<I> as Iterator>::Item) -> Acc,` [src]

#### `pub unsafe fn __iterator_get_unchecked(
&mut self,
idx: usize
) -> <Enumerate<I> as Iterator>::Itemⓘ

### Notable traits for Enumerate<I>

`impl<I> Iterator for Enumerate<I> where
I: Iterator, type Item = (usize, <I as Iterator>::Item);`
where
Enumerate<I>: TrustedRandomAccess,` [src]

### `impl<I> Iterator for Fuse<I> where
I: Iterator,` [src]

#### `type Item = <I as Iterator>::Item`

#### `pub fn next(&mut self) -> Option<<Fuse<I> as Iterator>::Item>`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn last(self) -> Option<<Fuse<I> as Iterator>::Item>`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<Acc, Fold, R>(&mut self, acc: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <Fuse<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Fuse<I>: Sized,` [src]

#### `pub fn fold<Acc, Fold>(self, acc: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <Fuse<I> as Iterator>::Item) -> Acc,` [src]

#### `pub fn find<P>(&mut self, predicate: P) -> Option<<Fuse<I> as Iterator>::Item> where
P: FnMut(&<Fuse<I> as Iterator>::Item) -> bool,` [src]

#### `pub unsafe fn __iterator_get_unchecked(
&mut self,
idx: usize
) -> <Fuse<I> as Iterator>::Itemⓘ

### Notable traits for Fuse<I>

`impl<I> Iterator for Fuse<I> where
I: Iterator, type Item = <I as Iterator>::Item;`
where
Fuse<I>: TrustedRandomAccess,` [src]

### `impl<I> Iterator for Peekable<I> where
I: Iterator,` [src]

#### `type Item = <I as Iterator>::Item`

#### `pub fn next(&mut self) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn last(self) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
F: FnMut(B, <Peekable<I> as Iterator>::Item) -> R,
R: Try<Ok = B>,
Peekable<I>: Sized,` [src]

#### `pub fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <Peekable<I> as Iterator>::Item) -> Acc,` [src]

### `impl<I> Iterator for Rev<I> where
I: DoubleEndedIterator,` [src]

#### `type Item = <I as Iterator>::Item`

#### `pub fn next(&mut self) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn advance_by(&mut self, n: usize) -> Result<(), usize>`[src]

🔬 This is a nightly-only experimental API. (`iter_advance_by` #77404)

recently added

#### `pub fn nth(&mut self, n: usize) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
F: FnMut(B, <Rev<I> as Iterator>::Item) -> R,
R: Try<Ok = B>,
Rev<I>: Sized,` [src]

#### `pub fn fold<Acc, F>(self, init: Acc, f: F) -> Acc where
F: FnMut(Acc, <Rev<I> as Iterator>::Item) -> Acc,` [src]

#### `pub fn find<P>(&mut self, predicate: P) -> Option<<Rev<I> as Iterator>::Item> where
P: FnMut(&<Rev<I> as Iterator>::Item) -> bool,` [src]

### `impl<I> Iterator for Skip<I> where
I: Iterator,` [src]

#### `type Item = <I as Iterator>::Item`

#### `pub fn next(&mut self) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn last(self) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <Skip<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Skip<I>: Sized,` [src]

#### `pub fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <Skip<I> as Iterator>::Item) -> Acc,` [src]

### `impl<I> Iterator for StepBy<I> where
I: Iterator,` [src]

#### `type Item = <I as Iterator>::Item`

#### `pub fn next(&mut self) -> Option<<StepBy<I> as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<<StepBy<I> as Iterator>::Item>`[src]

#### `pub fn try_fold<Acc, F, R>(&mut self, acc: Acc, f: F) -> R where
F: FnMut(Acc, <StepBy<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,` [src]

#### `pub fn fold<Acc, F>(self, acc: Acc, f: F) -> Acc where
F: FnMut(Acc, <StepBy<I> as Iterator>::Item) -> Acc,` [src]

### `impl<I> Iterator for Take<I> where
I: Iterator,` [src]

#### `type Item = <I as Iterator>::Item`

#### `pub fn next(&mut self) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <Take<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Take<I>: Sized,` [src]

#### `pub fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <Take<I> as Iterator>::Item) -> Acc,
Take<I>: Sized,` [src]

### `impl<I, A> Iterator for Box<I, A> where
A: Allocator,
I: Iterator + ?Sized,` [src]

#### `type Item = <I as Iterator>::Item`

#### `pub fn next(&mut self) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn nth(&mut self, n: usize) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn last(self) -> Option<<I as Iterator>::Item>`[src]

### `impl<I, F> Iterator for Inspect<I, F> where
F: FnMut(&<I as Iterator>::Item),
I: Iterator,` [src]

#### `type Item = <I as Iterator>::Item`

#### `pub fn next(&mut self) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <Inspect<I, F> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Inspect<I, F>: Sized,` [src]

#### `pub fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <Inspect<I, F> as Iterator>::Item) -> Acc,` [src]

### `impl<I, P> Iterator for Filter<I, P> where
I: Iterator,
P: FnMut(&<I as Iterator>::Item) -> bool,` [src]

#### `type Item = <I as Iterator>::Item`

#### `pub fn next(&mut self) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <Filter<I, P> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Filter<I, P>: Sized,` [src]

#### `pub fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <Filter<I, P> as Iterator>::Item) -> Acc,` [src]

### `impl<I, P> Iterator for SkipWhile<I, P> where
I: Iterator,
P: FnMut(&<I as Iterator>::Item) -> bool,` [src]

#### `type Item = <I as Iterator>::Item`

#### `pub fn next(&mut self) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <SkipWhile<I, P> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
SkipWhile<I, P>: Sized,` [src]

#### `pub fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <SkipWhile<I, P> as Iterator>::Item) -> Acc,` [src]

### `impl<I, P> Iterator for TakeWhile<I, P> where
I: Iterator,
P: FnMut(&<I as Iterator>::Item) -> bool,` [src]

#### `type Item = <I as Iterator>::Item`

#### `pub fn next(&mut self) -> Option<<I as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <TakeWhile<I, P> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
TakeWhile<I, P>: Sized,` [src]

#### `pub fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <TakeWhile<I, P> as Iterator>::Item) -> Acc,
TakeWhile<I, P>: Sized,` [src]

### `impl<I, U> Iterator for Flatten<I> where
I: Iterator,
U: Iterator,
<I as Iterator>::Item: IntoIterator,
<<I as Iterator>::Item as IntoIterator>::IntoIter == U,
<<I as Iterator>::Item as IntoIterator>::Item == <U as Iterator>::Item,` [src]

#### `type Item = <U as Iterator>::Item`

#### `pub fn next(&mut self) -> Option<<U as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <Flatten<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Flatten<I>: Sized,` [src]

#### `pub fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <Flatten<I> as Iterator>::Item) -> Acc,` [src]

### `impl<I, U, F> Iterator for FlatMap<I, U, F> where
F: FnMut(<I as Iterator>::Item) -> U,
I: Iterator,
U: IntoIterator,` [src]

#### `type Item = <U as IntoIterator>::Item`

#### `pub fn next(&mut self) -> Option<<U as IntoIterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <FlatMap<I, U, F> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
FlatMap<I, U, F>: Sized,` [src]

#### `pub fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <FlatMap<I, U, F> as Iterator>::Item) -> Acc,` [src]

### `impl<K> Iterator for std::collections::hash_set::IntoIter<K>`[src]

#### `type Item = K`

#### `pub fn next(&mut self) -> Option<K>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<K, F, '_> Iterator for std::collections::hash_set::DrainFilter<'_, K, F> where
F: FnMut(&K) -> bool,` [src]

#### `type Item = K`

#### `pub fn next(&mut self) -> Option<K>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<K, V> Iterator for std::collections::btree_map::IntoIter<K, V>`[src]

#### `type Item = (K, V)`

#### `pub fn next(&mut self) -> Option<(K, V)>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<K, V> Iterator for std::collections::btree_map::IntoKeys<K, V>`[src]

#### `type Item = K`

#### `pub fn next(&mut self) -> Option<K>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn last(self) -> Option<K>`[src]

#### `pub fn min(self) -> Option<K>`[src]

#### `pub fn max(self) -> Option<K>`[src]

### `impl<K, V> Iterator for std::collections::btree_map::IntoValues<K, V>`[src]

#### `type Item = V`

#### `pub fn next(&mut self) -> Option<V>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn last(self) -> Option<V>`[src]

### `impl<K, V> Iterator for std::collections::hash_map::IntoIter<K, V>`[src]

#### `type Item = (K, V)`

#### `pub fn next(&mut self) -> Option<(K, V)>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<K, V> Iterator for std::collections::hash_map::IntoKeys<K, V>`[src]

#### `type Item = K`

#### `pub fn next(&mut self) -> Option<K>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<K, V> Iterator for std::collections::hash_map::IntoValues<K, V>`[src]

#### `type Item = V`

#### `pub fn next(&mut self) -> Option<V>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<K, V, F, '_> Iterator for std::collections::hash_map::DrainFilter<'_, K, V, F> where
F: FnMut(&K, &mut V) -> bool,` [src]

#### `type Item = (K, V)`

#### `pub fn next(&mut self) -> Option<(K, V)>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<R: Read> Iterator for std::io::Bytes<R>`[src]

#### `type Item = Result<u8>`

#### `pub fn next(&mut self) -> Option<Result<u8>>`[src]

### `impl<T> Iterator for std::collections::binary_heap::IntoIter<T>`[src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<T> Iterator for IntoIterSorted<T> where
T: Ord,` [src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<T> Iterator for std::collections::btree_set::IntoIter<T>`[src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<T> Iterator for std::collections::linked_list::IntoIter<T>`[src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<T> Iterator for std::collections::vec_deque::IntoIter<T>`[src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<T> Iterator for Empty<T>`[src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<T> Iterator for Once<T>`[src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<T> Iterator for std::result::IntoIter<T>`[src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<T> Iterator for std::sync::mpsc::IntoIter<T>`[src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

### `impl<T, A> Iterator for std::vec::IntoIter<T, A> where
A: Allocator,` [src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<T>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub unsafe fn __iterator_get_unchecked(
&mut self,
i: usize
) -> <IntoIter<T, A> as Iterator>::Itemⓘ

### Notable traits for IntoIter<T, A>

`impl<T, A> Iterator for IntoIter<T, A> where
A: Allocator, type Item = T;`
where
IntoIter<T, A>: TrustedRandomAccess,` [src]

### `impl<T, F> Iterator for FromFn<F> where
F: FnMut() -> Option<T>,` [src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<<FromFn<F> as Iterator>::Item>`[src]

### `impl<T, F> Iterator for Successors<T, F> where
F: FnMut(&T) -> Option<T>,` [src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<<Successors<T, F> as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

### `impl<T, const N: usize> Iterator for std::array::IntoIter<T, N>`[src]

#### `type Item = T`

#### `pub fn next(&mut self) -> Option<<IntoIter<T, N> as Iterator>::Item>`[src]

#### `pub fn size_hint(&self) -> (usize, Option<usize>)`[src]

#### `pub fn count(self) -> usize`[src]

#### `pub fn last(self) -> Option<<IntoIter<T, N> as Iterator>::Item>`[src]

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