# Struct std::collections::linked_list::LinkedList 1.0.0 [−] [src]

    pub struct LinkedList<T> {
        // some fields omitted
    }

A doubly-linked list.

## Methods

### `impl<T> LinkedList<T>`

#### `fn new() -> LinkedList<T>`

Creates an empty `LinkedList`.

#### `fn append(&mut self, other: &mut LinkedList<T>)`

Moves all elements from `other` to the end of the list.

This reuses all the nodes from `other` and moves them into `self`. After this operation, `other` becomes empty.

This operation should compute in O(1) time and O(1) memory.

# Examples

fn main() { use std::collections::LinkedList; let mut a = LinkedList::new(); let mut b = LinkedList::new(); a.push_back(1); a.push_back(2); b.push_back(3); b.push_back(4); a.append(&mut b); for e in &a { println!("{}", e); // prints 1, then 2, then 3, then 4 } println!("{}", b.len()); // prints 0 }

    use std::collections::LinkedList;

    let mut a = LinkedList::new();
    let mut b = LinkedList::new();
    a.push_back(1);
    a.push_back(2);
    b.push_back(3);
    b.push_back(4);

    a.append(&mut b);

    for e in &a {
        println!("{}", e); // prints 1, then 2, then 3, then 4
    }
    println!("{}", b.len()); // prints 0

#### `fn iter(&self) -> Iter<T>`

Provides a forward iterator.

#### `fn iter_mut(&mut self) -> IterMut<T>`

Provides a forward iterator with mutable references.

#### `fn is_empty(&self) -> bool`

Returns `true` if the `LinkedList` is empty.

This operation should compute in O(1) time.

# Examples

fn main() { use std::collections::LinkedList; let mut dl = LinkedList::new(); assert!(dl.is_empty()); dl.push_front("foo"); assert!(!dl.is_empty()); }

    use std::collections::LinkedList;

    let mut dl = LinkedList::new();
    assert!(dl.is_empty());

    dl.push_front("foo");
    assert!(!dl.is_empty());

#### `fn len(&self) -> usize`

Returns the length of the `LinkedList`.

This operation should compute in O(1) time.

# Examples

fn main() { use std::collections::LinkedList; let mut dl = LinkedList::new(); dl.push_front(2); assert_eq!(dl.len(), 1); dl.push_front(1); assert_eq!(dl.len(), 2); dl.push_back(3); assert_eq!(dl.len(), 3); }

    use std::collections::LinkedList;

    let mut dl = LinkedList::new();

    dl.push_front(2);
    assert_eq!(dl.len(), 1);

    dl.push_front(1);
    assert_eq!(dl.len(), 2);

    dl.push_back(3);
    assert_eq!(dl.len(), 3);

#### `fn clear(&mut self)`

Removes all elements from the `LinkedList`.

This operation should compute in O(n) time.

# Examples

fn main() { use std::collections::LinkedList; let mut dl = LinkedList::new(); dl.push_front(2); dl.push_front(1); assert_eq!(dl.len(), 2); assert_eq!(dl.front(), Some(&1)); dl.clear(); assert_eq!(dl.len(), 0); assert_eq!(dl.front(), None); }

    use std::collections::LinkedList;

    let mut dl = LinkedList::new();

    dl.push_front(2);
    dl.push_front(1);
    assert_eq!(dl.len(), 2);
    assert_eq!(dl.front(), Some(&1));

    dl.clear();
    assert_eq!(dl.len(), 0);
    assert_eq!(dl.front(), None);

#### `fn contains(&self, x: &T) -> bool where T: PartialEq<T>`

Unstable (`linked_list_contains` #32630)

: recently added

Returns `true` if the `LinkedList` contains an element equal to the given value.

#### `fn front(&self) -> Option<&T>`

Provides a reference to the front element, or `None` if the list is empty.

# Examples

fn main() { use std::collections::LinkedList; let mut dl = LinkedList::new(); assert_eq!(dl.front(), None); dl.push_front(1); assert_eq!(dl.front(), Some(&1)); }

    use std::collections::LinkedList;

    let mut dl = LinkedList::new();
    assert_eq!(dl.front(), None);

    dl.push_front(1);
    assert_eq!(dl.front(), Some(&1));

#### `fn front_mut(&mut self) -> Option<&mut T>`

Provides a mutable reference to the front element, or `None` if the list is empty.

# Examples

fn main() { use std::collections::LinkedList; let mut dl = LinkedList::new(); assert_eq!(dl.front(), None); dl.push_front(1); assert_eq!(dl.front(), Some(&1)); match dl.front_mut() { None => {}, Some(x) => *x = 5, } assert_eq!(dl.front(), Some(&5)); }

    use std::collections::LinkedList;

    let mut dl = LinkedList::new();
    assert_eq!(dl.front(), None);

    dl.push_front(1);
    assert_eq!(dl.front(), Some(&1));

    match dl.front_mut() {
        None => {},
        Some(x) => *x = 5,
    }
    assert_eq!(dl.front(), Some(&5));

#### `fn back(&self) -> Option<&T>`

Provides a reference to the back element, or `None` if the list is empty.

# Examples

fn main() { use std::collections::LinkedList; let mut dl = LinkedList::new(); assert_eq!(dl.back(), None); dl.push_back(1); assert_eq!(dl.back(), Some(&1)); }

    use std::collections::LinkedList;

    let mut dl = LinkedList::new();
    assert_eq!(dl.back(), None);

    dl.push_back(1);
    assert_eq!(dl.back(), Some(&1));

#### `fn back_mut(&mut self) -> Option<&mut T>`

Provides a mutable reference to the back element, or `None` if the list is empty.

# Examples

fn main() { use std::collections::LinkedList; let mut dl = LinkedList::new(); assert_eq!(dl.back(), None); dl.push_back(1); assert_eq!(dl.back(), Some(&1)); match dl.back_mut() { None => {}, Some(x) => *x = 5, } assert_eq!(dl.back(), Some(&5)); }

    use std::collections::LinkedList;

    let mut dl = LinkedList::new();
    assert_eq!(dl.back(), None);

    dl.push_back(1);
    assert_eq!(dl.back(), Some(&1));

    match dl.back_mut() {
        None => {},
        Some(x) => *x = 5,
    }
    assert_eq!(dl.back(), Some(&5));

#### `fn push_front(&mut self, elt: T)`

Adds an element first in the list.

This operation should compute in O(1) time.

# Examples

fn main() { use std::collections::LinkedList; let mut dl = LinkedList::new(); dl.push_front(2); assert_eq!(dl.front().unwrap(), &2); dl.push_front(1); assert_eq!(dl.front().unwrap(), &1); }

    use std::collections::LinkedList;

    let mut dl = LinkedList::new();

    dl.push_front(2);
    assert_eq!(dl.front().unwrap(), &2);

    dl.push_front(1);
    assert_eq!(dl.front().unwrap(), &1);

#### `fn pop_front(&mut self) -> Option<T>`

Removes the first element and returns it, or `None` if the list is empty.

This operation should compute in O(1) time.

# Examples

fn main() { use std::collections::LinkedList; let mut d = LinkedList::new(); assert_eq!(d.pop_front(), None); d.push_front(1); d.push_front(3); assert_eq!(d.pop_front(), Some(3)); assert_eq!(d.pop_front(), Some(1)); assert_eq!(d.pop_front(), None); }

    use std::collections::LinkedList;

    let mut d = LinkedList::new();
    assert_eq!(d.pop_front(), None);

    d.push_front(1);
    d.push_front(3);
    assert_eq!(d.pop_front(), Some(3));
    assert_eq!(d.pop_front(), Some(1));
    assert_eq!(d.pop_front(), None);

#### `fn push_back(&mut self, elt: T)`

Appends an element to the back of a list

# Examples

fn main() { use std::collections::LinkedList; let mut d = LinkedList::new(); d.push_back(1); d.push_back(3); assert_eq!(3, *d.back().unwrap()); }

    use std::collections::LinkedList;

    let mut d = LinkedList::new();
    d.push_back(1);
    d.push_back(3);
    assert_eq!(3, *d.back().unwrap());

#### `fn pop_back(&mut self) -> Option<T>`

Removes the last element from a list and returns it, or `None` if it is empty.

# Examples

fn main() { use std::collections::LinkedList; let mut d = LinkedList::new(); assert_eq!(d.pop_back(), None); d.push_back(1); d.push_back(3); assert_eq!(d.pop_back(), Some(3)); }

    use std::collections::LinkedList;

    let mut d = LinkedList::new();
    assert_eq!(d.pop_back(), None);
    d.push_back(1);
    d.push_back(3);
    assert_eq!(d.pop_back(), Some(3));

#### `fn split_off(&mut self, at: usize) -> LinkedList<T>`

Splits the list into two at the given index. Returns everything after the given index, including the index.

# Panics

Panics if `at > len`.

This operation should compute in O(n) time.

# Examples

fn main() { use std::collections::LinkedList; let mut d = LinkedList::new(); d.push_front(1); d.push_front(2); d.push_front(3); let mut splitted = d.split_off(2); assert_eq!(splitted.pop_front(), Some(1)); assert_eq!(splitted.pop_front(), None); }

    use std::collections::LinkedList;

    let mut d = LinkedList::new();

    d.push_front(1);
    d.push_front(2);
    d.push_front(3);

    let mut splitted = d.split_off(2);

    assert_eq!(splitted.pop_front(), Some(1));
    assert_eq!(splitted.pop_front(), None);

#### `fn front_place(&mut self) -> FrontPlace<T>`

Unstable (`collection_placement` #30172)

: method name and placement protocol are subject to change

Returns a place for insertion at the front of the list.

Using this method with placement syntax is equivalent to `push_front`, but may be more efficient.

# Examples

#![feature(collection_placement)] #![feature(placement_in_syntax)] fn main() { use std::collections::LinkedList; let mut list = LinkedList::new(); list.front_place() <- 2; list.front_place() <- 4; assert!(list.iter().eq(&[4, 2])); }

    #![feature(collection_placement)]
    #![feature(placement_in_syntax)]

    use std::collections::LinkedList;

    let mut list = LinkedList::new();
    list.front_place() <- 2;
    list.front_place() <- 4;
    assert!(list.iter().eq(&[4, 2]));

#### `fn back_place(&mut self) -> BackPlace<T>`

Unstable (`collection_placement` #30172)

: method name and placement protocol are subject to change

Returns a place for insertion at the back of the list.

Using this method with placement syntax is equivalent to `push_back`, but may be more efficient.

# Examples

#![feature(collection_placement)] #![feature(placement_in_syntax)] fn main() { use std::collections::LinkedList; let mut list = LinkedList::new(); list.back_place() <- 2; list.back_place() <- 4; assert!(list.iter().eq(&[2, 4])); }

    #![feature(collection_placement)]
    #![feature(placement_in_syntax)]

    use std::collections::LinkedList;

    let mut list = LinkedList::new();
    list.back_place() <- 2;
    list.back_place() <- 4;
    assert!(list.iter().eq(&[2, 4]));

## Trait Implementations

### `impl<T> Default for LinkedList<T>`

#### `fn default() -> LinkedList<T>`

Returns the "default value" for a type. Read more

### `impl<T> Drop for LinkedList<T>`

#### `fn drop(&mut self)`

A method called when the value goes out of scope. Read more

### `impl<T> FromIterator<T> for LinkedList<T>`

#### `fn from_iter<I>(iter: I) -> LinkedList<T> where I: IntoIterator<Item=T>`

Creates a value from an iterator. Read more

### `impl<T> IntoIterator for LinkedList<T>`

#### `type Item = T`

The type of the elements being iterated over.

#### `type IntoIter = IntoIter<T>`

Which kind of iterator are we turning this into?

#### `fn into_iter(self) -> IntoIter<T>`

Consumes the list into an iterator yielding elements by value.

### `impl<'a, T> IntoIterator for &'a LinkedList<T>`

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

The type of the elements being iterated over.

#### `type IntoIter = Iter<'a, T>`

Which kind of iterator are we turning this into?

#### `fn into_iter(self) -> Iter<'a, T>`

Creates an iterator from a value. Read more

### `impl<'a, T> IntoIterator for &'a mut LinkedList<T>`

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

The type of the elements being iterated over.

#### `type IntoIter = IterMut<'a, T>`

Which kind of iterator are we turning this into?

#### `fn into_iter(self) -> IterMut<'a, T>`

Creates an iterator from a value. Read more

### `impl<T> Extend<T> for LinkedList<T>`

#### `fn extend<I>(&mut self, iter: I) where I: IntoIterator<Item=T>`

Extends a collection with the contents of an iterator. Read more

### `impl<'a, T> Extend<&'a T> for LinkedList<T> where T: Copy + 'a`
1.2.0

#### `fn extend<I>(&mut self, iter: I) where I: IntoIterator<Item=&'a T>`

Extends a collection with the contents of an iterator. Read more

### `impl<T> PartialEq<LinkedList<T>> for LinkedList<T> where T: PartialEq<T>`

#### `fn eq(&self, other: &LinkedList<T>) -> bool`

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

#### `fn ne(&self, other: &LinkedList<T>) -> bool`

This method tests for `!=`.

### `impl<T> Eq for LinkedList<T> where T: Eq`

### `impl<T> PartialOrd<LinkedList<T>> for LinkedList<T> where T: PartialOrd<T>`

#### `fn partial_cmp(&self, other: &LinkedList<T>) -> Option<Ordering>`

This method returns an ordering between `self` and `other` values if one exists. Read more

#### `fn lt(&self, other: &Rhs) -> bool`

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more

#### `fn le(&self, other: &Rhs) -> bool`

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more

#### `fn gt(&self, other: &Rhs) -> bool`

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more

#### `fn ge(&self, other: &Rhs) -> bool`

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more

### `impl<T> Ord for LinkedList<T> where T: Ord`

#### `fn cmp(&self, other: &LinkedList<T>) -> Ordering`

This method returns an `Ordering` between `self` and `other`. Read more

### `impl<T> Clone for LinkedList<T> where T: Clone`

#### `fn clone(&self) -> LinkedList<T>`

Returns a copy of the value. Read more

#### `fn clone_from(&mut self, source: &Self)`

Performs copy-assignment from `source`. Read more

### `impl<T> Debug for LinkedList<T> where T: Debug`

#### `fn fmt(&self, f: &mut Formatter) -> Result<(), Error>`

Formats the value using the given formatter.

### `impl<T> Hash for LinkedList<T> where T: Hash`

#### `fn hash<H>(&self, state: &mut H) where H: Hasher`

Feeds this value into the state given, updating the hasher as necessary.

#### `fn hash_slice<H>(data: &[Self], state: &mut H) where H: Hasher`
1.3.0

Feeds a slice of this type into the state provided.

### `impl<T> Send for LinkedList<T> where T: Send`

### `impl<T> Sync for LinkedList<T> where T: Sync`

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