# 1.36.0[−][src]Struct std::io::IoSlice

    #[repr(transparent)]pub struct IoSlice<'a>(_);

A buffer type used with `Write::write_vectored`.

It is semantically a wrapper around an `&[u8]`, but is guaranteed to be ABI compatible with the `iovec` type on Unix platforms and `WSABUF` on Windows.

## Implementations

### `impl<'a> IoSlice<'a>`[src]

#### `pub fn new(buf: &'a [u8]) -> IoSlice<'a>`[src]

Creates a new `IoSlice` wrapping a byte slice.

# Panics

Panics on Windows if the slice is larger than 4GB.

#### `pub fn advance<'b>(
bufs: &'b mut [IoSlice<'a>],
n: usize
) -> &'b mut [IoSlice<'a>]ⓘ

### Notable traits for &'_ [u8]

`impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]`
`[src]

🔬 This is a nightly-only experimental API. (`io_slice_advance` #62726)

Advance the internal cursor of the slice.

# Notes

Elements in the slice may be modified if the cursor is not advanced to the end of the slice. For example if we have a slice of buffers with 2 `IoSlice`s, both of length 8, and we advance the cursor by 10 bytes the first `IoSlice` will be untouched however the second will be modified to remove the first 2 bytes (10 - 8).

# Examples

    #![feature(io_slice_advance)]

    use std::io::IoSlice;
    use std::ops::Deref;

    let buf1 = [1; 8];
    let buf2 = [2; 16];
    let buf3 = [3; 8];
    let mut bufs = &mut [
        IoSlice::new(&buf1),
        IoSlice::new(&buf2),
        IoSlice::new(&buf3),
    ][..];

    // Mark 10 bytes as written.
    bufs = IoSlice::advance(bufs, 10);
    assert_eq!(bufs[0].deref(), [2; 14].as_ref());
    assert_eq!(bufs[1].deref(), [3; 8].as_ref());

Run

## Methods from Deref<Target = [u8]>

#### `pub const fn len(&self) -> usize` 1.0.0 (const: 1.32.0)[src]

Returns the number of elements in the slice.

# Examples

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

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#### `pub const fn is_empty(&self) -> bool` 1.0.0 (const: 1.32.0)[src]

Returns `true` if the slice has a length of 0.

# Examples

    let a = [1, 2, 3];
    assert!(!a.is_empty());

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#### `pub fn first(&self) -> Option<&T>`1.0.0[src]

Returns the first element of the slice, or `None` if it is empty.

# Examples

    let v = [10, 40, 30];
    assert_eq!(Some(&10), v.first());

    let w: &[i32] = &[];
    assert_eq!(None, w.first());

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#### `pub fn split_first(&self) -> Option<(&T, &[T])>`1.5.0[src]

Returns the first and all the rest of the elements of the slice, or `None` if it is empty.

# Examples

    let x = &[0, 1, 2];

    if let Some((first, elements)) = x.split_first() {
        assert_eq!(first, &0);
        assert_eq!(elements, &[1, 2]);
    }

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#### `pub fn split_last(&self) -> Option<(&T, &[T])>`1.5.0[src]

Returns the last and all the rest of the elements of the slice, or `None` if it is empty.

# Examples

    let x = &[0, 1, 2];

    if let Some((last, elements)) = x.split_last() {
        assert_eq!(last, &2);
        assert_eq!(elements, &[0, 1]);
    }

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#### `pub fn last(&self) -> Option<&T>`1.0.0[src]

Returns the last element of the slice, or `None` if it is empty.

# Examples

    let v = [10, 40, 30];
    assert_eq!(Some(&30), v.last());

    let w: &[i32] = &[];
    assert_eq!(None, w.last());

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#### `pub fn get<I>(&self, index: I) -> Option<&<I as SliceIndex<[T]>>::Output> where
I: SliceIndex<[T]>,` 1.0.0[src]

Returns a reference to an element or subslice depending on the type of index.

- If given a position, returns a reference to the element at that position or `None` if out of bounds.
- If given a range, returns the subslice corresponding to that range, or `None` if out of bounds.

# Examples

    let v = [10, 40, 30];
    assert_eq!(Some(&40), v.get(1));
    assert_eq!(Some(&[10, 40][..]), v.get(0..2));
    assert_eq!(None, v.get(3));
    assert_eq!(None, v.get(0..4));

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#### `pub unsafe fn get_unchecked<I>(
&self,
index: I
) -> &<I as SliceIndex<[T]>>::Output where
I: SliceIndex<[T]>,` 1.0.0[src]

Returns a reference to an element or subslice, without doing bounds checking.

For a safe alternative see `get`.

# Safety

Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used.

# Examples

    let x = &[1, 2, 4];

    unsafe {
        assert_eq!(x.get_unchecked(1), &2);
    }

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#### `pub const fn as_ptr(&self) -> *const T` 1.0.0 (const: 1.32.0)[src]

Returns a raw pointer to the slice's buffer.

The caller must ensure that the slice outlives the pointer this function returns, or else it will end up pointing to garbage.

The caller must also ensure that the memory the pointer (non-transitively) points to is never written to (except inside an `UnsafeCell`) using this pointer or any pointer derived from it. If you need to mutate the contents of the slice, use `as_mut_ptr`.

Modifying the container referenced by this slice may cause its buffer to be reallocated, which would also make any pointers to it invalid.

# Examples

    let x = &[1, 2, 4];
    let x_ptr = x.as_ptr();

    unsafe {
        for i in 0..x.len() {
            assert_eq!(x.get_unchecked(i), &*x_ptr.add(i));
        }
    }

Run

#### `pub fn as_ptr_range(&self) -> Range<*const T>ⓘ

### Notable traits for Range<A>

`impl<A> Iterator for Range<A> where
A: Step, type Item = A;`
`1.48.0[src]

Returns the two raw pointers spanning the slice.

The returned range is half-open, which means that the end pointer points one past the last element of the slice. This way, an empty slice is represented by two equal pointers, and the difference between the two pointers represents the size of the slice.

See `as_ptr` for warnings on using these pointers. The end pointer requires extra caution, as it does not point to a valid element in the slice.

This function is useful for interacting with foreign interfaces which use two pointers to refer to a range of elements in memory, as is common in C++.

It can also be useful to check if a pointer to an element refers to an element of this slice:

    let a = [1, 2, 3];
    let x = &a[1] as *const _;
    let y = &5 as *const _;

    assert!(a.as_ptr_range().contains(&x));
    assert!(!a.as_ptr_range().contains(&y));

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#### `pub fn iter(&self) -> Iter<'_, T>ⓘ

### Notable traits for Iter<'a, T>

`impl<'a, T> Iterator for Iter<'a, T> type Item = &'a T;`
`1.0.0[src]

Returns an iterator over the slice.

# Examples

    let x = &[1, 2, 4];
    let mut iterator = x.iter();

    assert_eq!(iterator.next(), Some(&1));
    assert_eq!(iterator.next(), Some(&2));
    assert_eq!(iterator.next(), Some(&4));
    assert_eq!(iterator.next(), None);

Run

#### `pub fn windows(&self, size: usize) -> Windows<'_, T>ⓘ

### Notable traits for Windows<'a, T>

`impl<'a, T> Iterator for Windows<'a, T> type Item = &'a [T];`
`1.0.0[src]

Returns an iterator over all contiguous windows of length `size`. The windows overlap. If the slice is shorter than `size`, the iterator returns no values.

# Panics

Panics if `size` is 0.

# Examples

    let slice = ['r', 'u', 's', 't'];
    let mut iter = slice.windows(2);
    assert_eq!(iter.next().unwrap(), &['r', 'u']);
    assert_eq!(iter.next().unwrap(), &['u', 's']);
    assert_eq!(iter.next().unwrap(), &['s', 't']);
    assert!(iter.next().is_none());

Run

If the slice is shorter than `size`:

    let slice = ['f', 'o', 'o'];
    let mut iter = slice.windows(4);
    assert!(iter.next().is_none());

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#### `pub fn chunks(&self, chunk_size: usize) -> Chunks<'_, T>ⓘ

### Notable traits for Chunks<'a, T>

`impl<'a, T> Iterator for Chunks<'a, T> type Item = &'a [T];`
`1.0.0[src]

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the beginning of the slice.

The chunks are slices and do not overlap. If `chunk_size` does not divide the length of the slice, then the last chunk will not have length `chunk_size`.

See `chunks_exact` for a variant of this iterator that returns chunks of always exactly `chunk_size` elements, and `rchunks` for the same iterator but starting at the end of the slice.

# Panics

Panics if `chunk_size` is 0.

# Examples

    let slice = ['l', 'o', 'r', 'e', 'm'];
    let mut iter = slice.chunks(2);
    assert_eq!(iter.next().unwrap(), &['l', 'o']);
    assert_eq!(iter.next().unwrap(), &['r', 'e']);
    assert_eq!(iter.next().unwrap(), &['m']);
    assert!(iter.next().is_none());

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#### `pub fn chunks_exact(&self, chunk_size: usize) -> ChunksExact<'_, T>ⓘ

### Notable traits for ChunksExact<'a, T>

`impl<'a, T> Iterator for ChunksExact<'a, T> type Item = &'a [T];`
`1.31.0[src]

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the beginning of the slice.

The chunks are slices and do not overlap. If `chunk_size` does not divide the length of the slice, then the last up to `chunk_size-1` elements will be omitted and can be retrieved from the `remainder` function of the iterator.

Due to each chunk having exactly `chunk_size` elements, the compiler can often optimize the resulting code better than in the case of `chunks`.

See `chunks` for a variant of this iterator that also returns the remainder as a smaller chunk, and `rchunks_exact` for the same iterator but starting at the end of the slice.

# Panics

Panics if `chunk_size` is 0.

# Examples

    let slice = ['l', 'o', 'r', 'e', 'm'];
    let mut iter = slice.chunks_exact(2);
    assert_eq!(iter.next().unwrap(), &['l', 'o']);
    assert_eq!(iter.next().unwrap(), &['r', 'e']);
    assert!(iter.next().is_none());
    assert_eq!(iter.remainder(), &['m']);

Run

#### `pub fn as_chunks<const N: usize>(&self) -> (&[[T; N]], &[T])`[src]

🔬 This is a nightly-only experimental API. (`slice_as_chunks` #74985)

Splits the slice into a slice of `N`-element arrays, starting at the beginning of the slice, and a remainder slice with length strictly less than `N`.

# Panics

Panics if `N` is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

# Examples

    #![feature(slice_as_chunks)]
    let slice = ['l', 'o', 'r', 'e', 'm'];
    let (chunks, remainder) = slice.as_chunks();
    assert_eq!(chunks, &[['l', 'o'], ['r', 'e']]);
    assert_eq!(remainder, &['m']);

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#### `pub fn array_chunks<const N: usize>(&self) -> ArrayChunks<'_, T, N>ⓘ

### Notable traits for ArrayChunks<'a, T, N>

`impl<'a, T, const N: usize> Iterator for ArrayChunks<'a, T, N> type Item = &'a [T; N];`
`[src]

🔬 This is a nightly-only experimental API. (`array_chunks` #74985)

Returns an iterator over `N` elements of the slice at a time, starting at the beginning of the slice.

The chunks are array references and do not overlap. If `N` does not divide the length of the slice, then the last up to `N-1` elements will be omitted and can be retrieved from the `remainder` function of the iterator.

This method is the const generic equivalent of `chunks_exact`.

# Panics

Panics if `N` is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

# Examples

    #![feature(array_chunks)]
    let slice = ['l', 'o', 'r', 'e', 'm'];
    let mut iter = slice.array_chunks();
    assert_eq!(iter.next().unwrap(), &['l', 'o']);
    assert_eq!(iter.next().unwrap(), &['r', 'e']);
    assert!(iter.next().is_none());
    assert_eq!(iter.remainder(), &['m']);

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#### `pub fn array_windows<const N: usize>(&self) -> ArrayWindows<'_, T, N>ⓘ

### Notable traits for ArrayWindows<'a, T, N>

`impl<'a, T, const N: usize> Iterator for ArrayWindows<'a, T, N> type Item = &'a [T; N];`
`[src]

🔬 This is a nightly-only experimental API. (`array_windows` #75027)

Returns an iterator over overlapping windows of `N` elements of a slice, starting at the beginning of the slice.

This is the const generic equivalent of `windows`.

If `N` is greater than the size of the slice, it will return no windows.

# Panics

Panics if `N` is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

# Examples

    #![feature(array_windows)]
    let slice = [0, 1, 2, 3];
    let mut iter = slice.array_windows();
    assert_eq!(iter.next().unwrap(), &[0, 1]);
    assert_eq!(iter.next().unwrap(), &[1, 2]);
    assert_eq!(iter.next().unwrap(), &[2, 3]);
    assert!(iter.next().is_none());

Run

#### `pub fn rchunks(&self, chunk_size: usize) -> RChunks<'_, T>ⓘ

### Notable traits for RChunks<'a, T>

`impl<'a, T> Iterator for RChunks<'a, T> type Item = &'a [T];`
`1.31.0[src]

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the end of the slice.

The chunks are slices and do not overlap. If `chunk_size` does not divide the length of the slice, then the last chunk will not have length `chunk_size`.

See `rchunks_exact` for a variant of this iterator that returns chunks of always exactly `chunk_size` elements, and `chunks` for the same iterator but starting at the beginning of the slice.

# Panics

Panics if `chunk_size` is 0.

# Examples

    let slice = ['l', 'o', 'r', 'e', 'm'];
    let mut iter = slice.rchunks(2);
    assert_eq!(iter.next().unwrap(), &['e', 'm']);
    assert_eq!(iter.next().unwrap(), &['o', 'r']);
    assert_eq!(iter.next().unwrap(), &['l']);
    assert!(iter.next().is_none());

Run

#### `pub fn rchunks_exact(&self, chunk_size: usize) -> RChunksExact<'_, T>ⓘ

### Notable traits for RChunksExact<'a, T>

`impl<'a, T> Iterator for RChunksExact<'a, T> type Item = &'a [T];`
`1.31.0[src]

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the end of the slice.

The chunks are slices and do not overlap. If `chunk_size` does not divide the length of the slice, then the last up to `chunk_size-1` elements will be omitted and can be retrieved from the `remainder` function of the iterator.

Due to each chunk having exactly `chunk_size` elements, the compiler can often optimize the resulting code better than in the case of `chunks`.

See `rchunks` for a variant of this iterator that also returns the remainder as a smaller chunk, and `chunks_exact` for the same iterator but starting at the beginning of the slice.

# Panics

Panics if `chunk_size` is 0.

# Examples

    let slice = ['l', 'o', 'r', 'e', 'm'];
    let mut iter = slice.rchunks_exact(2);
    assert_eq!(iter.next().unwrap(), &['e', 'm']);
    assert_eq!(iter.next().unwrap(), &['o', 'r']);
    assert!(iter.next().is_none());
    assert_eq!(iter.remainder(), &['l']);

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#### `pub fn split_at(&self, mid: usize) -> (&[T], &[T])`1.0.0[src]

Divides one slice into two at an index.

The first will contain all indices from `[0, mid)` (excluding the index `mid` itself) and the second will contain all indices from `[mid, len)` (excluding the index `len` itself).

# Panics

Panics if `mid > len`.

# Examples

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

    {
       let (left, right) = v.split_at(0);
       assert_eq!(left, []);
       assert_eq!(right, [1, 2, 3, 4, 5, 6]);
    }

    {
        let (left, right) = v.split_at(2);
        assert_eq!(left, [1, 2]);
        assert_eq!(right, [3, 4, 5, 6]);
    }

    {
        let (left, right) = v.split_at(6);
        assert_eq!(left, [1, 2, 3, 4, 5, 6]);
        assert_eq!(right, []);
    }

Run

#### `pub fn split<F>(&self, pred: F) -> Split<'_, T, F>ⓘ

### Notable traits for Split<'a, T, P>

`impl<'a, T, P> Iterator for Split<'a, T, P> where
P: FnMut(&T) -> bool, type Item = &'a [T];`
where
F: FnMut(&T) -> bool,` 1.0.0[src]

Returns an iterator over subslices separated by elements that match `pred`. The matched element is not contained in the subslices.

# Examples

    let slice = [10, 40, 33, 20];
    let mut iter = slice.split(|num| num % 3 == 0);

    assert_eq!(iter.next().unwrap(), &[10, 40]);
    assert_eq!(iter.next().unwrap(), &[20]);
    assert!(iter.next().is_none());

Run

If the first element is matched, an empty slice will be the first item returned by the iterator. Similarly, if the last element in the slice is matched, an empty slice will be the last item returned by the iterator:

    let slice = [10, 40, 33];
    let mut iter = slice.split(|num| num % 3 == 0);

    assert_eq!(iter.next().unwrap(), &[10, 40]);
    assert_eq!(iter.next().unwrap(), &[]);
    assert!(iter.next().is_none());

Run

If two matched elements are directly adjacent, an empty slice will be present between them:

    let slice = [10, 6, 33, 20];
    let mut iter = slice.split(|num| num % 3 == 0);

    assert_eq!(iter.next().unwrap(), &[10]);
    assert_eq!(iter.next().unwrap(), &[]);
    assert_eq!(iter.next().unwrap(), &[20]);
    assert!(iter.next().is_none());

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#### `pub fn split_inclusive<F>(&self, pred: F) -> SplitInclusive<'_, T, F>ⓘ

### Notable traits for SplitInclusive<'a, T, P>

`impl<'a, T, P> Iterator for SplitInclusive<'a, T, P> where
P: FnMut(&T) -> bool, type Item = &'a [T];`
where
F: FnMut(&T) -> bool,` [src]

🔬 This is a nightly-only experimental API. (`split_inclusive` #72360)

Returns an iterator over subslices separated by elements that match `pred`. The matched element is contained in the end of the previous subslice as a terminator.

# Examples

    #![feature(split_inclusive)]
    let slice = [10, 40, 33, 20];
    let mut iter = slice.split_inclusive(|num| num % 3 == 0);

    assert_eq!(iter.next().unwrap(), &[10, 40, 33]);
    assert_eq!(iter.next().unwrap(), &[20]);
    assert!(iter.next().is_none());

Run

If the last element of the slice is matched, that element will be considered the terminator of the preceding slice. That slice will be the last item returned by the iterator.

    #![feature(split_inclusive)]
    let slice = [3, 10, 40, 33];
    let mut iter = slice.split_inclusive(|num| num % 3 == 0);

    assert_eq!(iter.next().unwrap(), &[3]);
    assert_eq!(iter.next().unwrap(), &[10, 40, 33]);
    assert!(iter.next().is_none());

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#### `pub fn rsplit<F>(&self, pred: F) -> RSplit<'_, T, F>ⓘ

### Notable traits for RSplit<'a, T, P>

`impl<'a, T, P> Iterator for RSplit<'a, T, P> where
P: FnMut(&T) -> bool, type Item = &'a [T];`
where
F: FnMut(&T) -> bool,` 1.27.0[src]

Returns an iterator over subslices separated by elements that match `pred`, starting at the end of the slice and working backwards. The matched element is not contained in the subslices.

# Examples

    let slice = [11, 22, 33, 0, 44, 55];
    let mut iter = slice.rsplit(|num| *num == 0);

    assert_eq!(iter.next().unwrap(), &[44, 55]);
    assert_eq!(iter.next().unwrap(), &[11, 22, 33]);
    assert_eq!(iter.next(), None);

Run

As with `split()`, if the first or last element is matched, an empty slice will be the first (or last) item returned by the iterator.

    let v = &[0, 1, 1, 2, 3, 5, 8];
    let mut it = v.rsplit(|n| *n % 2 == 0);
    assert_eq!(it.next().unwrap(), &[]);
    assert_eq!(it.next().unwrap(), &[3, 5]);
    assert_eq!(it.next().unwrap(), &[1, 1]);
    assert_eq!(it.next().unwrap(), &[]);
    assert_eq!(it.next(), None);

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#### `pub fn splitn<F>(&self, n: usize, pred: F) -> SplitN<'_, T, F>ⓘ

### Notable traits for SplitN<'a, T, P>

`impl<'a, T, P> Iterator for SplitN<'a, T, P> where
P: FnMut(&T) -> bool, type Item = &'a [T];`
where
F: FnMut(&T) -> bool,` 1.0.0[src]

Returns an iterator over subslices separated by elements that match `pred`, limited to returning at most `n` items. The matched element is not contained in the subslices.

The last element returned, if any, will contain the remainder of the slice.

# Examples

Print the slice split once by numbers divisible by 3 (i.e., `[10, 40]`, `[20, 60, 50]`):

    let v = [10, 40, 30, 20, 60, 50];

    for group in v.splitn(2, |num| *num % 3 == 0) {
        println!("{:?}", group);
    }

Run

#### `pub fn rsplitn<F>(&self, n: usize, pred: F) -> RSplitN<'_, T, F>ⓘ

### Notable traits for RSplitN<'a, T, P>

`impl<'a, T, P> Iterator for RSplitN<'a, T, P> where
P: FnMut(&T) -> bool, type Item = &'a [T];`
where
F: FnMut(&T) -> bool,` 1.0.0[src]

Returns an iterator over subslices separated by elements that match `pred` limited to returning at most `n` items. This starts at the end of the slice and works backwards. The matched element is not contained in the subslices.

The last element returned, if any, will contain the remainder of the slice.

# Examples

Print the slice split once, starting from the end, by numbers divisible by 3 (i.e., `[50]`, `[10, 40, 30, 20]`):

    let v = [10, 40, 30, 20, 60, 50];

    for group in v.rsplitn(2, |num| *num % 3 == 0) {
        println!("{:?}", group);
    }

Run

#### `pub fn contains(&self, x: &T) -> bool where
T: PartialEq<T>,` 1.0.0[src]

Returns `true` if the slice contains an element with the given value.

# Examples

    let v = [10, 40, 30];
    assert!(v.contains(&30));
    assert!(!v.contains(&50));

Run

If you do not have an `&T`, but just an `&U` such that `T: Borrow<U>` (e.g. `String: Borrow<str>`), you can use `iter().any`:

    let v = [String::from("hello"), String::from("world")]; // slice of `String`
    assert!(v.iter().any(|e| e == "hello")); // search with `&str`
    assert!(!v.iter().any(|e| e == "hi"));

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#### `pub fn starts_with(&self, needle: &[T]) -> bool where
T: PartialEq<T>,` 1.0.0[src]

Returns `true` if `needle` is a prefix of the slice.

# Examples

    let v = [10, 40, 30];
    assert!(v.starts_with(&[10]));
    assert!(v.starts_with(&[10, 40]));
    assert!(!v.starts_with(&[50]));
    assert!(!v.starts_with(&[10, 50]));

Run

Always returns `true` if `needle` is an empty slice:

    let v = &[10, 40, 30];
    assert!(v.starts_with(&[]));
    let v: &[u8] = &[];
    assert!(v.starts_with(&[]));

Run

#### `pub fn ends_with(&self, needle: &[T]) -> bool where
T: PartialEq<T>,` 1.0.0[src]

Returns `true` if `needle` is a suffix of the slice.

# Examples

    let v = [10, 40, 30];
    assert!(v.ends_with(&[30]));
    assert!(v.ends_with(&[40, 30]));
    assert!(!v.ends_with(&[50]));
    assert!(!v.ends_with(&[50, 30]));

Run

Always returns `true` if `needle` is an empty slice:

    let v = &[10, 40, 30];
    assert!(v.ends_with(&[]));
    let v: &[u8] = &[];
    assert!(v.ends_with(&[]));

Run

#### `#[must_use = "returns the subslice without modifying the original"]pub fn strip_prefix(&self, prefix: &[T]) -> Option<&[T]> where
T: PartialEq<T>,` [src]

🔬 This is a nightly-only experimental API. (`slice_strip` #73413)

Returns a subslice with the prefix removed.

If the slice starts with `prefix`, returns the subslice after the prefix, wrapped in `Some`. If `prefix` is empty, simply returns the original slice.

If the slice does not start with `prefix`, returns `None`.

# Examples

    #![feature(slice_strip)]
    let v = &[10, 40, 30];
    assert_eq!(v.strip_prefix(&[10]), Some(&[40, 30][..]));
    assert_eq!(v.strip_prefix(&[10, 40]), Some(&[30][..]));
    assert_eq!(v.strip_prefix(&[50]), None);
    assert_eq!(v.strip_prefix(&[10, 50]), None);

Run

#### `#[must_use = "returns the subslice without modifying the original"]pub fn strip_suffix(&self, suffix: &[T]) -> Option<&[T]> where
T: PartialEq<T>,` [src]

🔬 This is a nightly-only experimental API. (`slice_strip` #73413)

Returns a subslice with the suffix removed.

If the slice ends with `suffix`, returns the subslice before the suffix, wrapped in `Some`. If `suffix` is empty, simply returns the original slice.

If the slice does not end with `suffix`, returns `None`.

# Examples

    #![feature(slice_strip)]
    let v = &[10, 40, 30];
    assert_eq!(v.strip_suffix(&[30]), Some(&[10, 40][..]));
    assert_eq!(v.strip_suffix(&[40, 30]), Some(&[10][..]));
    assert_eq!(v.strip_suffix(&[50]), None);
    assert_eq!(v.strip_suffix(&[50, 30]), None);

Run

#### `pub fn binary_search(&self, x: &T) -> Result<usize, usize> where
T: Ord,` 1.0.0[src]

Binary searches this sorted slice for a given element.

If the value is found then `Result::Ok` is returned, containing the index of the matching element. If there are multiple matches, then any one of the matches could be returned. If the value is not found then `Result::Err` is returned, containing the index where a matching element could be inserted while maintaining sorted order.

# Examples

Looks up a series of four elements. The first is found, with a uniquely determined position; the second and third are not found; the fourth could match any position in `[1, 4]`.

    let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];

    assert_eq!(s.binary_search(&13),  Ok(9));
    assert_eq!(s.binary_search(&4),   Err(7));
    assert_eq!(s.binary_search(&100), Err(13));
    let r = s.binary_search(&1);
    assert!(match r { Ok(1..=4) => true, _ => false, });

Run

If you want to insert an item to a sorted vector, while maintaining sort order:

    let mut s = vec![0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];
    let num = 42;
    let idx = s.binary_search(&num).unwrap_or_else(|x| x);
    s.insert(idx, num);
    assert_eq!(s, [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 42, 55]);

Run

#### `pub fn binary_search_by<'a, F>(&'a self, f: F) -> Result<usize, usize> where
F: FnMut(&'a T) -> Ordering,` 1.0.0[src]

Binary searches this sorted slice with a comparator function.

The comparator function should implement an order consistent with the sort order of the underlying slice, returning an order code that indicates whether its argument is `Less`, `Equal` or `Greater` the desired target.

If the value is found then `Result::Ok` is returned, containing the index of the matching element. If there are multiple matches, then any one of the matches could be returned. If the value is not found then `Result::Err` is returned, containing the index where a matching element could be inserted while maintaining sorted order.

# Examples

Looks up a series of four elements. The first is found, with a uniquely determined position; the second and third are not found; the fourth could match any position in `[1, 4]`.

    let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];

    let seek = 13;
    assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Ok(9));
    let seek = 4;
    assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Err(7));
    let seek = 100;
    assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Err(13));
    let seek = 1;
    let r = s.binary_search_by(|probe| probe.cmp(&seek));
    assert!(match r { Ok(1..=4) => true, _ => false, });

Run

#### `pub fn binary_search_by_key<'a, B, F>(
&'a self,
b: &B,
f: F
) -> Result<usize, usize> where
B: Ord,
F: FnMut(&'a T) -> B,` 1.10.0[src]

Binary searches this sorted slice with a key extraction function.

Assumes that the slice is sorted by the key, for instance with `sort_by_key` using the same key extraction function.

If the value is found then `Result::Ok` is returned, containing the index of the matching element. If there are multiple matches, then any one of the matches could be returned. If the value is not found then `Result::Err` is returned, containing the index where a matching element could be inserted while maintaining sorted order.

# Examples

Looks up a series of four elements in a slice of pairs sorted by their second elements. The first is found, with a uniquely determined position; the second and third are not found; the fourth could match any position in `[1, 4]`.

    let s = [(0, 0), (2, 1), (4, 1), (5, 1), (3, 1),
             (1, 2), (2, 3), (4, 5), (5, 8), (3, 13),
             (1, 21), (2, 34), (4, 55)];

    assert_eq!(s.binary_search_by_key(&13, |&(a, b)| b),  Ok(9));
    assert_eq!(s.binary_search_by_key(&4, |&(a, b)| b),   Err(7));
    assert_eq!(s.binary_search_by_key(&100, |&(a, b)| b), Err(13));
    let r = s.binary_search_by_key(&1, |&(a, b)| b);
    assert!(match r { Ok(1..=4) => true, _ => false, });

Run

#### `pub unsafe fn align_to<U>(&self) -> (&[T], &[U], &[T])`1.30.0[src]

Transmute the slice to a slice of another type, ensuring alignment of the types is maintained.

This method splits the slice into three distinct slices: prefix, correctly aligned middle slice of a new type, and the suffix slice. The method may make the middle slice the greatest length possible for a given type and input slice, but only your algorithm's performance should depend on that, not its correctness. It is permissible for all of the input data to be returned as the prefix or suffix slice.

This method has no purpose when either input element `T` or output element `U` are zero-sized and will return the original slice without splitting anything.

# Safety

This method is essentially a `transmute` with respect to the elements in the returned middle slice, so all the usual caveats pertaining to `transmute::<T, U>` also apply here.

# Examples

Basic usage:

    unsafe {
        let bytes: [u8; 7] = [1, 2, 3, 4, 5, 6, 7];
        let (prefix, shorts, suffix) = bytes.align_to::<u16>();
        // less_efficient_algorithm_for_bytes(prefix);
        // more_efficient_algorithm_for_aligned_shorts(shorts);
        // less_efficient_algorithm_for_bytes(suffix);
    }

Run

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

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

new API

Checks if the elements of this slice are sorted.

That is, for each element `a` and its following element `b`, `a <= b` must hold. If the slice 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)]
    let empty: [i32; 0] = [];

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

Run

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

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

new API

Checks if the elements of this slice 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.

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

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

new API

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

Instead of comparing the slice'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"].is_sorted_by_key(|s| s.len()));
    assert!(![-2i32, -1, 0, 3].is_sorted_by_key(|n| n.abs()));

Run

#### `pub fn partition_point<P>(&self, pred: P) -> usize where
P: FnMut(&T) -> bool,` [src]

🔬 This is a nightly-only experimental API. (`partition_point` #73831)

new API

Returns the index of the partition point according to the given predicate (the index of the first element of the second partition).

The slice is assumed to be partitioned according to the given predicate. This means that all elements for which the predicate returns true are at the start of the slice and all elements for which the predicate returns false are at the end. For example, [7, 15, 3, 5, 4, 12, 6] is a partitioned under the predicate x % 2 != 0 (all odd numbers are at the start, all even at the end).

If this slice is not partitioned, the returned result is unspecified and meaningless, as this method performs a kind of binary search.

# Examples

    #![feature(partition_point)]

    let v = [1, 2, 3, 3, 5, 6, 7];
    let i = v.partition_point(|&x| x < 5);

    assert_eq!(i, 4);
    assert!(v[..i].iter().all(|&x| x < 5));
    assert!(v[i..].iter().all(|&x| !(x < 5)));

Run

#### `pub fn is_ascii(&self) -> bool` 1.23.0[src]

Checks if all bytes in this slice are within the ASCII range.

#### `pub fn eq_ignore_ascii_case(&self, other: &[u8]) -> bool` 1.23.0[src]

Checks that two slices are an ASCII case-insensitive match.

Same as `to_ascii_lowercase(a) == to_ascii_lowercase(b)`, but without allocating and copying temporaries.

#### `pub fn to_vec(&self) -> Vec<T, Global>ⓘ

### Notable traits for Vec<u8>

`impl Write for Vec<u8>`
where
T: Clone,` 1.0.0[src]

Copies `self` into a new `Vec`.

# Examples

    let s = [10, 40, 30];
    let x = s.to_vec();
    // Here, `s` and `x` can be modified independently.

Run

#### `pub fn to_vec_in<A>(&self, alloc: A) -> Vec<T, A>ⓘ

### Notable traits for Vec<u8>

`impl Write for Vec<u8>`
where
A: Allocator,
T: Clone,` [src]

🔬 This is a nightly-only experimental API. (`allocator_api` #32838)

Copies `self` into a new `Vec` with an allocator.

# Examples

    #![feature(allocator_api)]

    use std::alloc::System;

    let s = [10, 40, 30];
    let x = s.to_vec_in(System);
    // Here, `s` and `x` can be modified independently.

Run

#### `pub fn repeat(&self, n: usize) -> Vec<T, Global>ⓘ

### Notable traits for Vec<u8>

`impl Write for Vec<u8>`
where
T: Copy,` 1.40.0[src]

Creates a vector by repeating a slice `n` times.

# Panics

This function will panic if the capacity would overflow.

# Examples

Basic usage:

    assert_eq!([1, 2].repeat(3), vec![1, 2, 1, 2, 1, 2]);

Run

A panic upon overflow:

ⓘThis example panics

    // this will panic at runtime
    b"0123456789abcdef".repeat(usize::MAX);

Run

#### `pub fn concat<Item>(&self) -> <[T] as Concat<Item>>::Outputⓘ

### Notable traits for &'_ [u8]

`impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]`
where
Item: ?Sized,
[T]: Concat<Item>,` 1.0.0[src]

Flattens a slice of `T` into a single value `Self::Output`.

# Examples

    assert_eq!(["hello", "world"].concat(), "helloworld");
    assert_eq!([[1, 2], [3, 4]].concat(), [1, 2, 3, 4]);

Run

#### `pub fn join<Separator>(
&self,
sep: Separator
) -> <[T] as Join<Separator>>::Outputⓘ

### Notable traits for &'_ [u8]

`impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]`
where
[T]: Join<Separator>,` 1.3.0[src]

Flattens a slice of `T` into a single value `Self::Output`, placing a given separator between each.

# Examples

    assert_eq!(["hello", "world"].join(" "), "hello world");
    assert_eq!([[1, 2], [3, 4]].join(&0), [1, 2, 0, 3, 4]);
    assert_eq!([[1, 2], [3, 4]].join(&[0, 0][..]), [1, 2, 0, 0, 3, 4]);

Run

#### `pub fn connect<Separator>(
&self,
sep: Separator
) -> <[T] as Join<Separator>>::Outputⓘ

### Notable traits for &'_ [u8]

`impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]`
where
[T]: Join<Separator>,` 1.0.0[src]

👎 Deprecated since 1.3.0:

renamed to join

Flattens a slice of `T` into a single value `Self::Output`, placing a given separator between each.

# Examples

    assert_eq!(["hello", "world"].connect(" "), "hello world");
    assert_eq!([[1, 2], [3, 4]].connect(&0), [1, 2, 0, 3, 4]);

Run

#### `pub fn to_ascii_uppercase(&self) -> Vec<u8, Global>ⓘ

### Notable traits for Vec<u8>

`impl Write for Vec<u8>`
`1.23.0[src]

Returns a vector containing a copy of this slice where each byte is mapped to its ASCII upper case equivalent.

ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', but non-ASCII letters are unchanged.

To uppercase the value in-place, use `make_ascii_uppercase`.

#### `pub fn to_ascii_lowercase(&self) -> Vec<u8, Global>ⓘ

### Notable traits for Vec<u8>

`impl Write for Vec<u8>`
`1.23.0[src]

Returns a vector containing a copy of this slice where each byte is mapped to its ASCII lower case equivalent.

ASCII letters 'A' to 'Z' are mapped to 'a' to 'z', but non-ASCII letters are unchanged.

To lowercase the value in-place, use `make_ascii_lowercase`.

## Trait Implementations

### `impl<'a> Clone for IoSlice<'a>`[src]

#### `pub fn clone(&self) -> IoSlice<'a>`[src]

Returns a copy of the value. Read more

#### `pub fn clone_from(&mut self, source: &Self)`1.0.0[src]

Performs copy-assignment from `source`. Read more

### `impl<'a> Copy for IoSlice<'a>`[src]

### `impl<'a> Debug for IoSlice<'a>`[src]

#### `pub fn fmt(&self, fmt: &mut Formatter<'_>) -> Result`[src]

Formats the value using the given formatter. Read more

### `impl<'a> Deref for IoSlice<'a>`[src]

#### `type Target = [u8]`

The resulting type after dereferencing.

#### `pub fn deref(&self) -> &[u8]ⓘ

### Notable traits for &'_ [u8]

`impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]`
`[src]

Dereferences the value.

### `impl<'a> Send for IoSlice<'a>`1.44.0[src]

### `impl<'a> Sync for IoSlice<'a>`1.44.0[src]

## Auto Trait Implementations

### `impl<'a> RefUnwindSafe for IoSlice<'a>`

### `impl<'a> Unpin for IoSlice<'a>`

### `impl<'a> UnwindSafe for IoSlice<'a>`

## Blanket Implementations

### `impl<T> Any for T where
T: 'static + ?Sized,` [src]

#### `pub fn type_id(&self) -> TypeId`[src]

Gets the `TypeId` of `self`. Read more

### `impl<T> Borrow<T> for T where
T: ?Sized,` [src]

#### `pub fn borrow(&self) -> &Tⓘ

### 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]

Immutably borrows from an owned value. Read more

### `impl<T> BorrowMut<T> for T where
T: ?Sized,` [src]

#### `pub fn borrow_mut(&mut self) -> &mut Tⓘ

### 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]

Mutably borrows from an owned value. Read more

### `impl<T> From<T> for T`[src]

#### `pub fn from(t: T) -> T`[src]

Performs the conversion.

### `impl<T, U> Into<U> for T where
U: From<T>,` [src]

#### `pub fn into(self) -> U`[src]

Performs the conversion.

### `impl<T> ToOwned for T where
T: Clone,` [src]

#### `type Owned = T`

The resulting type after obtaining ownership.

#### `pub fn to_owned(&self) -> T`[src]

Creates owned data from borrowed data, usually by cloning. Read more

#### `pub fn clone_into(&self, target: &mut T)`[src]

🔬 This is a nightly-only experimental API. (`toowned_clone_into` #41263)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

### `impl<T, U> TryFrom<U> for T where
U: Into<T>,` [src]

#### `type Error = Infallible`

The type returned in the event of a conversion error.

#### `pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>`[src]

Performs the conversion.

### `impl<T, U> TryInto<U> for T where
U: TryFrom<T>,` [src]

#### `type Error = <U as TryFrom<T>>::Error`

The type returned in the event of a conversion error.

#### `pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>`[src]

Performs the conversion.