std::vec::Vec - Rust
Description: API documentation for the Rust `Vec` struct in crate `std`.
Keywords: rust, rustlang, rust-lang, Vec

# Struct std::vec::Vec 1.0.0 [−] [src]

    pub struct Vec<T> { /* fields omitted */ }

A contiguous growable array type, written `Vec<T>` but pronounced 'vector'.

# Examples

    let mut vec = Vec::new();
    vec.push(1);
    vec.push(2);

    assert_eq!(vec.len(), 2);
    assert_eq!(vec[0], 1);

    assert_eq!(vec.pop(), Some(2));
    assert_eq!(vec.len(), 1);

    vec[0] = 7;
    assert_eq!(vec[0], 7);

    vec.extend([1, 2, 3].iter().cloned());

    for x in &vec {
        println!("{}", x);
    }
    assert_eq!(vec, [7, 1, 2, 3]);Run

The `vec!` macro is provided to make initialization more convenient:

    let mut vec = vec![1, 2, 3];
    vec.push(4);
    assert_eq!(vec, [1, 2, 3, 4]);Run

It can also initialize each element of a `Vec<T>` with a given value:

    let vec = vec![0; 5];
    assert_eq!(vec, [0, 0, 0, 0, 0]);Run

Use a `Vec<T>` as an efficient stack:

    let mut stack = Vec::new();

    stack.push(1);
    stack.push(2);
    stack.push(3);

    while let Some(top) = stack.pop() {
        // Prints 3, 2, 1
        println!("{}", top);
    }Run

# Indexing

The `Vec` type allows to access values by index, because it implements the `Index` trait. An example will be more explicit:

    let v = vec![0, 2, 4, 6];
    println!("{}", v[1]); // it will display '2'Run

However be careful: if you try to access an index which isn't in the `Vec`, your software will panic! You cannot do this:

    let v = vec![0, 2, 4, 6];
    println!("{}", v[6]); // it will panic!Run

In conclusion: always check if the index you want to get really exists before doing it.

# Slicing

A `Vec` can be mutable. Slices, on the other hand, are read-only objects. To get a slice, use `&`. Example:

    fn read_slice(slice: &[usize]) {
        // ...
    }

    let v = vec![0, 1];
    read_slice(&v);

    // ... and that's all!
    // you can also do it like this:
    let x : &[usize] = &v;Run

In Rust, it's more common to pass slices as arguments rather than vectors when you just want to provide a read access. The same goes for `String` and `&str`.

# Capacity and reallocation

The capacity of a vector is the amount of space allocated for any future elements that will be added onto the vector. This is not to be confused with the length of a vector, which specifies the number of actual elements within the vector. If a vector's length exceeds its capacity, its capacity will automatically be increased, but its elements will have to be reallocated.

For example, a vector with capacity 10 and length 0 would be an empty vector with space for 10 more elements. Pushing 10 or fewer elements onto the vector will not change its capacity or cause reallocation to occur. However, if the vector's length is increased to 11, it will have to reallocate, which can be slow. For this reason, it is recommended to use `Vec::with_capacity` whenever possible to specify how big the vector is expected to get.

# Guarantees

Due to its incredibly fundamental nature, `Vec` makes a lot of guarantees about its design. This ensures that it's as low-overhead as possible in the general case, and can be correctly manipulated in primitive ways by unsafe code. Note that these guarantees refer to an unqualified `Vec<T>`. If additional type parameters are added (e.g. to support custom allocators), overriding their defaults may change the behavior.

Most fundamentally, `Vec` is and always will be a (pointer, capacity, length) triplet. No more, no less. The order of these fields is completely unspecified, and you should use the appropriate methods to modify these. The pointer will never be null, so this type is null-pointer-optimized.

However, the pointer may not actually point to allocated memory. In particular, if you construct a `Vec` with capacity 0 via `Vec::new`, `vec![]`, `Vec::with_capacity(0)`, or by calling `shrink_to_fit` on an empty Vec, it will not allocate memory. Similarly, if you store zero-sized types inside a `Vec`, it will not allocate space for them. Note that in this case the `Vec` may not report a `capacity` of 0. `Vec` will allocate if and only if `mem::size_of::<T>``() * capacity() > 0`. In general, `Vec`'s allocation details are subtle enough that it is strongly recommended that you only free memory allocated by a `Vec` by creating a new `Vec` and dropping it.

If a `Vec` has allocated memory, then the memory it points to is on the heap (as defined by the allocator Rust is configured to use by default), and its pointer points to `len` initialized elements in order (what you would see if you coerced it to a slice), followed by `capacity``-``len` logically uninitialized elements.

`Vec` will never perform a "small optimization" where elements are actually stored on the stack for two reasons:

- It would make it more difficult for unsafe code to correctly manipulate a `Vec`. The contents of a `Vec` wouldn't have a stable address if it were only moved, and it would be more difficult to determine if a `Vec` had actually allocated memory.

- It would penalize the general case, incurring an additional branch on every access.

`Vec` will never automatically shrink itself, even if completely empty. This ensures no unnecessary allocations or deallocations occur. Emptying a `Vec` and then filling it back up to the same `len` should incur no calls to the allocator. If you wish to free up unused memory, use `shrink_to_fit`.

`push` and `insert` will never (re)allocate if the reported capacity is sufficient. `push` and `insert` will (re)allocate if `len``==``capacity`. That is, the reported capacity is completely accurate, and can be relied on. It can even be used to manually free the memory allocated by a `Vec` if desired. Bulk insertion methods may reallocate, even when not necessary.

`Vec` does not guarantee any particular growth strategy when reallocating when full, nor when `reserve` is called. The current strategy is basic and it may prove desirable to use a non-constant growth factor. Whatever strategy is used will of course guarantee `O(1)` amortized `push`.

`vec![x; n]`, `vec![a, b, c, d]`, and `Vec::with_capacity(n)`, will all produce a `Vec` with exactly the requested capacity. If `len``==``capacity`, (as is the case for the `vec!` macro), then a `Vec<T>` can be converted to and from a `Box<[T]>` without reallocating or moving the elements.

`Vec` will not specifically overwrite any data that is removed from it, but also won't specifically preserve it. Its uninitialized memory is scratch space that it may use however it wants. It will generally just do whatever is most efficient or otherwise easy to implement. Do not rely on removed data to be erased for security purposes. Even if you drop a `Vec`, its buffer may simply be reused by another `Vec`. Even if you zero a `Vec`'s memory first, that may not actually happen because the optimizer does not consider this a side-effect that must be preserved. There is one case which we will not break, however: using `unsafe` code to write to the excess capacity, and then increasing the length to match, is always valid.

`Vec` does not currently guarantee the order in which elements are dropped (the order has changed in the past, and may change again).

## Methods

### `impl<T> Vec<T>`
[src]

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

Constructs a new, empty `Vec<T>`.

The vector will not allocate until elements are pushed onto it.

# Examples

    let mut vec: Vec<i32> = Vec::new();Run

#### `fn with_capacity(capacity: usize) -> Vec<T>`

Constructs a new, empty `Vec<T>` with the specified capacity.

The vector will be able to hold exactly `capacity` elements without reallocating. If `capacity` is 0, the vector will not allocate.

It is important to note that this function does not specify the length of the returned vector, but only the capacity. For an explanation of the difference between length and capacity, see Capacity and reallocation.

# Examples

    let mut vec = Vec::with_capacity(10);

    // The vector contains no items, even though it has capacity for more
    assert_eq!(vec.len(), 0);

    // These are all done without reallocating...
    for i in 0..10 {
        vec.push(i);
    }

    // ...but this may make the vector reallocate
    vec.push(11);Run

#### `unsafe fn from_raw_parts(ptr: *mut T, length: usize, capacity: usize) -> Vec<T>`

Creates a `Vec<T>` directly from the raw components of another vector.

# Safety

This is highly unsafe, due to the number of invariants that aren't checked:

- `ptr` needs to have been previously allocated via `String`/`Vec<T>` (at least, it's highly likely to be incorrect if it wasn't).
- `length` needs to be less than or equal to `capacity`.
- `capacity` needs to be the capacity that the pointer was allocated with.

Violating these may cause problems like corrupting the allocator's internal datastructures. For example it is not safe to build a `Vec<u8>` from a pointer to a C `char` array and a `size_t`.

The ownership of `ptr` is effectively transferred to the `Vec<T>` which may then deallocate, reallocate or change the contents of memory pointed to by the pointer at will. Ensure that nothing else uses the pointer after calling this function.

# Examples

    use std::ptr;
    use std::mem;

    fn main() {
        let mut v = vec![1, 2, 3];

        // Pull out the various important pieces of information about `v`
        let p = v.as_mut_ptr();
        let len = v.len();
        let cap = v.capacity();

        unsafe {
            // Cast `v` into the void: no destructor run, so we are in
            // complete control of the allocation to which `p` points.
            mem::forget(v);

            // Overwrite memory with 4, 5, 6
            for i in 0..len as isize {
                ptr::write(p.offset(i), 4 + i);
            }

            // Put everything back together into a Vec
            let rebuilt = Vec::from_raw_parts(p, len, cap);
            assert_eq!(rebuilt, [4, 5, 6]);
        }
    }Run

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

Returns the number of elements the vector can hold without reallocating.

# Examples

    let vec: Vec<i32> = Vec::with_capacity(10);
    assert_eq!(vec.capacity(), 10);Run

#### `fn reserve(&mut self, additional: usize)`

Reserves capacity for at least `additional` more elements to be inserted in the given `Vec<T>`. The collection may reserve more space to avoid frequent reallocations. After calling `reserve`, capacity will be greater than or equal to `self.len() + additional`. Does nothing if capacity is already sufficient.

# Panics

Panics if the new capacity overflows `usize`.

# Examples

    let mut vec = vec![1];
    vec.reserve(10);
    assert!(vec.capacity() >= 11);Run

#### `fn reserve_exact(&mut self, additional: usize)`

Reserves the minimum capacity for exactly `additional` more elements to be inserted in the given `Vec<T>`. After calling `reserve_exact`, capacity will be greater than or equal to `self.len() + additional`. Does nothing if the capacity is already sufficient.

Note that the allocator may give the collection more space than it requests. Therefore capacity can not be relied upon to be precisely minimal. Prefer `reserve` if future insertions are expected.

# Panics

Panics if the new capacity overflows `usize`.

# Examples

    let mut vec = vec![1];
    vec.reserve_exact(10);
    assert!(vec.capacity() >= 11);Run

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

Shrinks the capacity of the vector as much as possible.

It will drop down as close as possible to the length but the allocator may still inform the vector that there is space for a few more elements.

# Examples

    let mut vec = Vec::with_capacity(10);
    vec.extend([1, 2, 3].iter().cloned());
    assert_eq!(vec.capacity(), 10);
    vec.shrink_to_fit();
    assert!(vec.capacity() >= 3);Run

#### `fn into_boxed_slice(self) -> Box<[T]>`

Converts the vector into `Box<[T]>`.

Note that this will drop any excess capacity. Calling this and converting back to a vector with `into_vec` is equivalent to calling `shrink_to_fit`.

# Examples

    let v = vec![1, 2, 3];

    let slice = v.into_boxed_slice();Run

Any excess capacity is removed:

    let mut vec = Vec::with_capacity(10);
    vec.extend([1, 2, 3].iter().cloned());

    assert_eq!(vec.capacity(), 10);
    let slice = vec.into_boxed_slice();
    assert_eq!(slice.into_vec().capacity(), 3);Run

#### `fn truncate(&mut self, len: usize)`

Shortens the vector, keeping the first `len` elements and dropping the rest.

If `len` is greater than the vector's current length, this has no effect.

The `drain` method can emulate `truncate`, but causes the excess elements to be returned instead of dropped.

Note that this method has no effect on the allocated capacity of the vector.

# Examples

Truncating a five element vector to two elements:

    let mut vec = vec![1, 2, 3, 4, 5];
    vec.truncate(2);
    assert_eq!(vec, [1, 2]);Run

No truncation occurs when `len` is greater than the vector's current length:

    let mut vec = vec![1, 2, 3];
    vec.truncate(8);
    assert_eq!(vec, [1, 2, 3]);Run

Truncating when `len == 0` is equivalent to calling the `clear` method.

    let mut vec = vec![1, 2, 3];
    vec.truncate(0);
    assert_eq!(vec, []);Run

#### `fn as_slice(&self) -> &[T]`
1.7.0

Extracts a slice containing the entire vector.

Equivalent to `&s[..]`.

# Examples

    use std::io::{self, Write};
    let buffer = vec![1, 2, 3, 5, 8];
    io::sink().write(buffer.as_slice()).unwrap();Run

#### `fn as_mut_slice(&mut self) -> &mut [T]`
1.7.0

Extracts a mutable slice of the entire vector.

Equivalent to `&mut s[..]`.

# Examples

    use std::io::{self, Read};
    let mut buffer = vec![0; 3];
    io::repeat(0b101).read_exact(buffer.as_mut_slice()).unwrap();Run

#### `unsafe fn set_len(&mut self, len: usize)`

Sets the length of a vector.

This will explicitly set the size of the vector, without actually modifying its buffers, so it is up to the caller to ensure that the vector is actually the specified size.

# Examples

    use std::ptr;

    let mut vec = vec!['r', 'u', 's', 't'];

    unsafe {
        ptr::drop_in_place(&mut vec[3]);
        vec.set_len(3);
    }
    assert_eq!(vec, ['r', 'u', 's']);Run

In this example, there is a memory leak since the memory locations owned by the inner vectors were not freed prior to the `set_len` call:

    let mut vec = vec![vec![1, 0, 0],
                       vec![0, 1, 0],
                       vec![0, 0, 1]];
    unsafe {
        vec.set_len(0);
    }Run

In this example, the vector gets expanded from zero to four items without any memory allocations occurring, resulting in vector values of unallocated memory:

    let mut vec: Vec<char> = Vec::new();

    unsafe {
        vec.set_len(4);
    }Run

#### `fn swap_remove(&mut self, index: usize) -> T`

Removes an element from the vector and returns it.

The removed element is replaced by the last element of the vector.

This does not preserve ordering, but is O(1).

# Panics

Panics if `index` is out of bounds.

# Examples

    let mut v = vec!["foo", "bar", "baz", "qux"];

    assert_eq!(v.swap_remove(1), "bar");
    assert_eq!(v, ["foo", "qux", "baz"]);

    assert_eq!(v.swap_remove(0), "foo");
    assert_eq!(v, ["baz", "qux"]);Run

#### `fn insert(&mut self, index: usize, element: T)`

Inserts an element at position `index` within the vector, shifting all elements after it to the right.

# Panics

Panics if `index` is out of bounds.

# Examples

    let mut vec = vec![1, 2, 3];
    vec.insert(1, 4);
    assert_eq!(vec, [1, 4, 2, 3]);
    vec.insert(4, 5);
    assert_eq!(vec, [1, 4, 2, 3, 5]);Run

#### `fn remove(&mut self, index: usize) -> T`

Removes and returns the element at position `index` within the vector, shifting all elements after it to the left.

# Panics

Panics if `index` is out of bounds.

# Examples

    let mut v = vec![1, 2, 3];
    assert_eq!(v.remove(1), 2);
    assert_eq!(v, [1, 3]);Run

#### `fn retain<F>(&mut self, f: F) where
F: FnMut(&T) -> bool,`

Retains only the elements specified by the predicate.

In other words, remove all elements `e` such that `f(&e)` returns `false`. This method operates in place and preserves the order of the retained elements.

# Examples

    let mut vec = vec![1, 2, 3, 4];
    vec.retain(|&x| x%2 == 0);
    assert_eq!(vec, [2, 4]);Run

#### `fn dedup_by_key<F, K>(&mut self, key: F) where
F: FnMut(&mut T) -> K,
K: PartialEq<K>,`
1.16.0

Removes all but the first of consecutive elements in the vector that resolve to the same key.

If the vector is sorted, this removes all duplicates.

# Examples

    let mut vec = vec![10, 20, 21, 30, 20];

    vec.dedup_by_key(|i| *i / 10);

    assert_eq!(vec, [10, 20, 30, 20]);Run

#### `fn dedup_by<F>(&mut self, same_bucket: F) where
F: FnMut(&mut T, &mut T) -> bool,`
1.16.0

Removes all but the first of consecutive elements in the vector satisfying a given equality relation.

The `same_bucket` function is passed references to two elements from the vector, and returns `true` if the elements compare equal, or `false` if they do not. The elements are passed in opposite order from their order in the vector, so if `same_bucket(a, b)` returns `true`, `a` is removed.

If the vector is sorted, this removes all duplicates.

# Examples

    use std::ascii::AsciiExt;

    let mut vec = vec!["foo", "bar", "Bar", "baz", "bar"];

    vec.dedup_by(|a, b| a.eq_ignore_ascii_case(b));

    assert_eq!(vec, ["foo", "bar", "baz", "bar"]);Run

#### `fn push(&mut self, value: T)`

Appends an element to the back of a collection.

# Panics

Panics if the number of elements in the vector overflows a `usize`.

# Examples

    let mut vec = vec![1, 2];
    vec.push(3);
    assert_eq!(vec, [1, 2, 3]);Run

#### `fn place_back(&mut self) -> PlaceBack<T>`

🔬 This is a nightly-only experimental API. (`collection_placement` #30172)

placement protocol is subject to change

Returns a place for insertion at the back of the `Vec`.

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

# Examples

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

    let mut vec = vec![1, 2];
    vec.place_back() <- 3;
    vec.place_back() <- 4;
    assert_eq!(&vec, &[1, 2, 3, 4]);Run

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

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

# Examples

    let mut vec = vec![1, 2, 3];
    assert_eq!(vec.pop(), Some(3));
    assert_eq!(vec, [1, 2]);Run

#### `fn append(&mut self, other: &mut Vec<T>)`
1.4.0

Moves all the elements of `other` into `Self`, leaving `other` empty.

# Panics

Panics if the number of elements in the vector overflows a `usize`.

# Examples

    let mut vec = vec![1, 2, 3];
    let mut vec2 = vec![4, 5, 6];
    vec.append(&mut vec2);
    assert_eq!(vec, [1, 2, 3, 4, 5, 6]);
    assert_eq!(vec2, []);Run

#### `fn drain<R>(&mut self, range: R) -> Drain<T> where
R: RangeArgument<usize>,`
1.6.0

Creates a draining iterator that removes the specified range in the vector and yields the removed items.

Note 1: The element range is removed even if the iterator is only partially consumed or not consumed at all.

Note 2: It is unspecified how many elements are removed from the vector if the `Drain` value is leaked.

# Panics

Panics if the starting point is greater than the end point or if the end point is greater than the length of the vector.

# Examples

    let mut v = vec![1, 2, 3];
    let u: Vec<_> = v.drain(1..).collect();
    assert_eq!(v, &[1]);
    assert_eq!(u, &[2, 3]);

    // A full range clears the vector
    v.drain(..);
    assert_eq!(v, &[]);Run

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

Clears the vector, removing all values.

Note that this method has no effect on the allocated capacity of the vector.

# Examples

    let mut v = vec![1, 2, 3];

    v.clear();

    assert!(v.is_empty());Run

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

Returns the number of elements in the vector, also referred to as its 'length'.

# Examples

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

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

Returns `true` if the vector contains no elements.

# Examples

    let mut v = Vec::new();
    assert!(v.is_empty());

    v.push(1);
    assert!(!v.is_empty());Run

#### `fn split_off(&mut self, at: usize) -> Vec<T>`
1.4.0

Splits the collection into two at the given index.

Returns a newly allocated `Self`. `self` contains elements `[0, at)`, and the returned `Self` contains elements `[at, len)`.

Note that the capacity of `self` does not change.

# Panics

Panics if `at > len`.

# Examples

    let mut vec = vec![1,2,3];
    let vec2 = vec.split_off(1);
    assert_eq!(vec, [1]);
    assert_eq!(vec2, [2, 3]);Run

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

#### `fn resize(&mut self, new_len: usize, value: T)`
1.5.0

Resizes the `Vec` in-place so that `len` is equal to `new_len`.

If `new_len` is greater than `len`, the `Vec` is extended by the difference, with each additional slot filled with `value`. If `new_len` is less than `len`, the `Vec` is simply truncated.

This method requires `Clone` to clone the passed value. If you'd rather create a value with `Default` instead, see `resize_default`.

# Examples

    let mut vec = vec!["hello"];
    vec.resize(3, "world");
    assert_eq!(vec, ["hello", "world", "world"]);

    let mut vec = vec![1, 2, 3, 4];
    vec.resize(2, 0);
    assert_eq!(vec, [1, 2]);Run

#### `fn extend_from_slice(&mut self, other: &[T])`
1.6.0

Clones and appends all elements in a slice to the `Vec`.

Iterates over the slice `other`, clones each element, and then appends it to this `Vec`. The `other` vector is traversed in-order.

Note that this function is same as `extend` except that it is specialized to work with slices instead. If and when Rust gets specialization this function will likely be deprecated (but still available).

# Examples

    let mut vec = vec![1];
    vec.extend_from_slice(&[2, 3, 4]);
    assert_eq!(vec, [1, 2, 3, 4]);Run

### `impl<T> Vec<T> where
T: Default,`
[src]

#### `fn resize_default(&mut self, new_len: usize)`

🔬 This is a nightly-only experimental API. (`vec_resize_default` #41758)

Resizes the `Vec` in-place so that `len` is equal to `new_len`.

If `new_len` is greater than `len`, the `Vec` is extended by the difference, with each additional slot filled with `Default::default()`. If `new_len` is less than `len`, the `Vec` is simply truncated.

This method uses `Default` to create new values on every push. If you'd rather `Clone` a given value, use `resize`.

# Examples

    #![feature(vec_resize_default)]

    let mut vec = vec![1, 2, 3];
    vec.resize_default(5);
    assert_eq!(vec, [1, 2, 3, 0, 0]);

    let mut vec = vec![1, 2, 3, 4];
    vec.resize_default(2);
    assert_eq!(vec, [1, 2]);Run

### `impl<T> Vec<T> where
T: PartialEq<T>,`
[src]

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

Removes consecutive repeated elements in the vector.

If the vector is sorted, this removes all duplicates.

# Examples

    let mut vec = vec![1, 2, 2, 3, 2];

    vec.dedup();

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

#### `fn remove_item(&mut self, item: &T) -> Option<T>`

🔬 This is a nightly-only experimental API. (`vec_remove_item` #40062)

recently added

Removes the first instance of `item` from the vector if the item exists.

# Examples

    let mut vec = vec![1, 2, 3, 1];

    vec.remove_item(&1);

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

### `impl<T> Vec<T>`
[src]

#### `fn splice<R, I>(
&mut self,
range: R,
replace_with: I
) -> Splice<<I as IntoIterator>::IntoIter> where
I: IntoIterator<Item = T>,
R: RangeArgument<usize>,`

🔬 This is a nightly-only experimental API. (`splice` #32310)

recently added

Creates a splicing iterator that replaces the specified range in the vector with the given `replace_with` iterator and yields the removed items. `replace_with` does not need to be the same length as `range`.

Note 1: The element range is removed even if the iterator is not consumed until the end.

Note 2: It is unspecified how many elements are removed from the vector, if the `Splice` value is leaked.

Note 3: The input iterator `replace_with` is only consumed when the `Splice` value is dropped.

Note 4: This is optimal if:

- The tail (elements in the vector after `range`) is empty,
- or `replace_with` yields fewer elements than `range`’s length
- or the lower bound of its `size_hint()` is exact.

Otherwise, a temporary vector is allocated and the tail is moved twice.

# Panics

Panics if the starting point is greater than the end point or if the end point is greater than the length of the vector.

# Examples

    #![feature(splice)]
    let mut v = vec![1, 2, 3];
    let new = [7, 8];
    let u: Vec<_> = v.splice(..2, new.iter().cloned()).collect();
    assert_eq!(v, &[7, 8, 3]);
    assert_eq!(u, &[1, 2]);Run

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

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

Returns the number of elements in the slice.

# Example

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

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

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

# Example

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

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

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());Run

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

Returns a mutable pointer to the first element of the slice, or `None` if it is empty.

# Examples

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

    if let Some(first) = x.first_mut() {
        *first = 5;
    }
    assert_eq!(x, &[5, 1, 2]);Run

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

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]);
    }Run

#### `fn split_first_mut(&mut self) -> Option<(&mut T, &mut [T])>`
1.5.0

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

# Examples

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

    if let Some((first, elements)) = x.split_first_mut() {
        *first = 3;
        elements[0] = 4;
        elements[1] = 5;
    }
    assert_eq!(x, &[3, 4, 5]);Run

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

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]);
    }Run

#### `fn split_last_mut(&mut self) -> Option<(&mut T, &mut [T])>`
1.5.0

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

# Examples

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

    if let Some((last, elements)) = x.split_last_mut() {
        *last = 3;
        elements[0] = 4;
        elements[1] = 5;
    }
    assert_eq!(x, &[4, 5, 3]);Run

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

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());Run

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

Returns a mutable pointer to the last item in the slice.

# Examples

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

    if let Some(last) = x.last_mut() {
        *last = 10;
    }
    assert_eq!(x, &[0, 1, 10]);Run

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

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));Run

#### `fn get_mut<I>(
&mut self,
index: I
) -> Option<&mut <I as SliceIndex<[T]>>::Output> where
I: SliceIndex<[T]>,`

Returns a mutable reference to an element or subslice depending on the type of index (see `get`) or `None` if the index is out of bounds.

# Examples

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

    if let Some(elem) = x.get_mut(1) {
        *elem = 42;
    }
    assert_eq!(x, &[0, 42, 2]);Run

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

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

This is generally not recommended, use with caution! For a safe alternative see `get`.

# Examples

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

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

#### `unsafe fn get_unchecked_mut<I>(
&mut self,
index: I
) -> &mut <I as SliceIndex<[T]>>::Output where
I: SliceIndex<[T]>,`

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

This is generally not recommended, use with caution! For a safe alternative see `get_mut`.

# Examples

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

    unsafe {
        let elem = x.get_unchecked_mut(1);
        *elem = 13;
    }
    assert_eq!(x, &[1, 13, 4]);Run

#### `fn as_ptr(&self) -> *const T`

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.

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.offset(i as isize));
        }
    }Run

#### `fn as_mut_ptr(&mut self) -> *mut T`

Returns an unsafe mutable 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.

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

    unsafe {
        for i in 0..x.len() {
            *x_ptr.offset(i as isize) += 2;
        }
    }
    assert_eq!(x, &[3, 4, 6]);Run

#### `fn swap(&mut self, a: usize, b: usize)`

Swaps two elements in the slice.

# Arguments

- a - The index of the first element
- b - The index of the second element

# Panics

Panics if `a` or `b` are out of bounds.

# Examples

    let mut v = ["a", "b", "c", "d"];
    v.swap(1, 3);
    assert!(v == ["a", "d", "c", "b"]);Run

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

Reverses the order of elements in the slice, in place.

# Example

    let mut v = [1, 2, 3];
    v.reverse();
    assert!(v == [3, 2, 1]);Run

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

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

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

Returns an iterator that allows modifying each value.

# Examples

    let x = &mut [1, 2, 4];
    for elem in x.iter_mut() {
        *elem += 2;
    }
    assert_eq!(x, &[3, 4, 6]);Run

#### `fn windows(&self, size: usize) -> Windows<T>`

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.

# Example

    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());Run

#### `fn chunks(&self, size: usize) -> Chunks<T>`

Returns an iterator over `size` elements of the slice at a time. The chunks are slices and do not overlap. If `size` does not divide the length of the slice, then the last chunk will not have length `size`.

# Panics

Panics if `size` is 0.

# Example

    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());Run

#### `fn chunks_mut(&mut self, chunk_size: usize) -> ChunksMut<T>`

Returns an iterator over `chunk_size` elements of the slice at a time. The chunks are mutable 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`.

# Panics

Panics if `chunk_size` is 0.

# Examples

    let v = &mut [0, 0, 0, 0, 0];
    let mut count = 1;

    for chunk in v.chunks_mut(2) {
        for elem in chunk.iter_mut() {
            *elem += count;
        }
        count += 1;
    }
    assert_eq!(v, &[1, 1, 2, 2, 3]);Run

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

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 = [10, 40, 30, 20, 50];
    let (v1, v2) = v.split_at(2);
    assert_eq!([10, 40], v1);
    assert_eq!([30, 20, 50], v2);Run

#### `fn split_at_mut(&mut self, mid: usize) -> (&mut [T], &mut [T])`

Divides one `&mut` 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 mut v = [1, 2, 3, 4, 5, 6];

    // scoped to restrict the lifetime of the borrows
    {
       let (left, right) = v.split_at_mut(0);
       assert!(left == []);
       assert!(right == [1, 2, 3, 4, 5, 6]);
    }

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

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

#### `fn split<F>(&self, pred: F) -> Split<T, F> where
F: FnMut(&T) -> bool,`

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());Run

#### `fn split_mut<F>(&mut self, pred: F) -> SplitMut<T, F> where
F: FnMut(&T) -> bool,`

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

# Examples

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

    for group in v.split_mut(|num| *num % 3 == 0) {
        group[0] = 1;
    }
    assert_eq!(v, [1, 40, 30, 1, 60, 1]);Run

#### `fn rsplit<F>(&self, pred: F) -> RSplit<T, F> where
F: FnMut(&T) -> bool,`

🔬 This is a nightly-only experimental API. (`slice_rsplit` #41020)

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

    #![feature(slice_rsplit)]

    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.

    #![feature(slice_rsplit)]

    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);Run

#### `fn rsplit_mut<F>(&mut self, pred: F) -> RSplitMut<T, F> where
F: FnMut(&T) -> bool,`

🔬 This is a nightly-only experimental API. (`slice_rsplit` #41020)

Returns an iterator over mutable 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

    #![feature(slice_rsplit)]

    let mut v = [100, 400, 300, 200, 600, 500];

    let mut count = 0;
    for group in v.rsplit_mut(|num| *num % 3 == 0) {
        count += 1;
        group[0] = count;
    }
    assert_eq!(v, [3, 400, 300, 2, 600, 1]);Run

#### `fn splitn<F>(&self, n: usize, pred: F) -> SplitN<T, F> where
F: FnMut(&T) -> bool,`

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

#### `fn splitn_mut<F>(&mut self, n: usize, pred: F) -> SplitNMut<T, F> where
F: FnMut(&T) -> bool,`

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

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

    for group in v.splitn_mut(2, |num| *num % 3 == 0) {
        group[0] = 1;
    }
    assert_eq!(v, [1, 40, 30, 1, 60, 50]);Run

#### `fn rsplitn<F>(&self, n: usize, pred: F) -> RSplitN<T, F> where
F: FnMut(&T) -> bool,`

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

#### `fn rsplitn_mut<F>(&mut self, n: usize, pred: F) -> RSplitNMut<T, F> where
F: FnMut(&T) -> bool,`

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

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

    for group in s.rsplitn_mut(2, |num| *num % 3 == 0) {
        group[0] = 1;
    }
    assert_eq!(s, [1, 40, 30, 20, 60, 1]);Run

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

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

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

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

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

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

#### `fn binary_search(&self, x: &T) -> Result<usize, usize> where
T: Ord,`

Binary searches this sorted slice for a given element.

If the value is found then `Ok` is returned, containing the index of the matching element; if the value is not found then `Err` is returned, containing the index where a matching element could be inserted while maintaining sorted order.

# Example

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

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

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 a matching value is found then returns `Ok`, containing the index for the matched element; if no match is found then `Err` is returned, containing the index where a matching element could be inserted while maintaining sorted order.

# Example

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

#### `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

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 a matching value is found then returns `Ok`, containing the index for the matched element; if no match is found then `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

#### `fn sort(&mut self) where
T: Ord,`

Sorts the slice.

This sort is stable (i.e. does not reorder equal elements) and `O(n log n)` worst-case.

When applicable, unstable sorting is preferred because it is generally faster than stable sorting and it doesn't allocate auxiliary memory. See `sort_unstable`.

# Current implementation

The current algorithm is an adaptive, iterative merge sort inspired by timsort. It is designed to be very fast in cases where the slice is nearly sorted, or consists of two or more sorted sequences concatenated one after another.

Also, it allocates temporary storage half the size of `self`, but for short slices a non-allocating insertion sort is used instead.

# Examples

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

    v.sort();
    assert!(v == [-5, -3, 1, 2, 4]);Run

#### `fn sort_by<F>(&mut self, compare: F) where
F: FnMut(&T, &T) -> Ordering,`

Sorts the slice with a comparator function.

This sort is stable (i.e. does not reorder equal elements) and `O(n log n)` worst-case.

When applicable, unstable sorting is preferred because it is generally faster than stable sorting and it doesn't allocate auxiliary memory. See `sort_unstable_by`.

# Current implementation

The current algorithm is an adaptive, iterative merge sort inspired by timsort. It is designed to be very fast in cases where the slice is nearly sorted, or consists of two or more sorted sequences concatenated one after another.

Also, it allocates temporary storage half the size of `self`, but for short slices a non-allocating insertion sort is used instead.

# Examples

    let mut v = [5, 4, 1, 3, 2];
    v.sort_by(|a, b| a.cmp(b));
    assert!(v == [1, 2, 3, 4, 5]);

    // reverse sorting
    v.sort_by(|a, b| b.cmp(a));
    assert!(v == [5, 4, 3, 2, 1]);Run

#### `fn sort_by_key<B, F>(&mut self, f: F) where
B: Ord,
F: FnMut(&T) -> B,`
1.7.0

Sorts the slice with a key extraction function.

This sort is stable (i.e. does not reorder equal elements) and `O(n log n)` worst-case.

When applicable, unstable sorting is preferred because it is generally faster than stable sorting and it doesn't allocate auxiliary memory. See `sort_unstable_by_key`.

# Current implementation

The current algorithm is an adaptive, iterative merge sort inspired by timsort. It is designed to be very fast in cases where the slice is nearly sorted, or consists of two or more sorted sequences concatenated one after another.

Also, it allocates temporary storage half the size of `self`, but for short slices a non-allocating insertion sort is used instead.

# Examples

    let mut v = [-5i32, 4, 1, -3, 2];

    v.sort_by_key(|k| k.abs());
    assert!(v == [1, 2, -3, 4, -5]);Run

#### `fn sort_unstable(&mut self) where
T: Ord,`
1.20.0

Sorts the slice, but may not preserve the order of equal elements.

This sort is unstable (i.e. may reorder equal elements), in-place (i.e. does not allocate), and `O(n log n)` worst-case.

# Current implementation

The current algorithm is based on Orson Peters' pattern-defeating quicksort, which is a quicksort variant designed to be very fast on certain kinds of patterns, sometimes achieving linear time. It is randomized but deterministic, and falls back to heapsort on degenerate inputs.

It is generally faster than stable sorting, except in a few special cases, e.g. when the slice consists of several concatenated sorted sequences.

# Examples

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

    v.sort_unstable();
    assert!(v == [-5, -3, 1, 2, 4]);Run

#### `fn sort_unstable_by<F>(&mut self, compare: F) where
F: FnMut(&T, &T) -> Ordering,`
1.20.0

Sorts the slice with a comparator function, but may not preserve the order of equal elements.

This sort is unstable (i.e. may reorder equal elements), in-place (i.e. does not allocate), and `O(n log n)` worst-case.

# Current implementation

The current algorithm is based on Orson Peters' pattern-defeating quicksort, which is a quicksort variant designed to be very fast on certain kinds of patterns, sometimes achieving linear time. It is randomized but deterministic, and falls back to heapsort on degenerate inputs.

It is generally faster than stable sorting, except in a few special cases, e.g. when the slice consists of several concatenated sorted sequences.

# Examples

    let mut v = [5, 4, 1, 3, 2];
    v.sort_unstable_by(|a, b| a.cmp(b));
    assert!(v == [1, 2, 3, 4, 5]);

    // reverse sorting
    v.sort_unstable_by(|a, b| b.cmp(a));
    assert!(v == [5, 4, 3, 2, 1]);Run

#### `fn sort_unstable_by_key<B, F>(&mut self, f: F) where
B: Ord,
F: FnMut(&T) -> B,`
1.20.0

Sorts the slice with a key extraction function, but may not preserve the order of equal elements.

This sort is unstable (i.e. may reorder equal elements), in-place (i.e. does not allocate), and `O(n log n)` worst-case.

# Current implementation

The current algorithm is based on Orson Peters' pattern-defeating quicksort, which is a quicksort variant designed to be very fast on certain kinds of patterns, sometimes achieving linear time. It is randomized but deterministic, and falls back to heapsort on degenerate inputs.

It is generally faster than stable sorting, except in a few special cases, e.g. when the slice consists of several concatenated sorted sequences.

# Examples

    let mut v = [-5i32, 4, 1, -3, 2];

    v.sort_unstable_by_key(|k| k.abs());
    assert!(v == [1, 2, -3, 4, -5]);Run

#### `fn rotate(&mut self, mid: usize)`

🔬 This is a nightly-only experimental API. (`slice_rotate` #41891)

Permutes the slice in-place such that `self[mid..]` moves to the beginning of the slice while `self[..mid]` moves to the end of the slice. Equivalently, rotates the slice `mid` places to the left or `k = self.len() - mid` places to the right.

This is a "k-rotation", a permutation in which item `i` moves to position `i + k`, modulo the length of the slice. See Elements of Programming §10.4.

Rotation by `mid` and rotation by `k` are inverse operations.

# Panics

This function will panic if `mid` is greater than the length of the slice. (Note that `mid == self.len()` does not panic; it's a nop rotation with `k == 0`, the inverse of a rotation with `mid == 0`.)

# Complexity

Takes linear (in `self.len()`) time.

# Examples

    #![feature(slice_rotate)]

    let mut a = [1, 2, 3, 4, 5, 6, 7];
    let mid = 2;
    a.rotate(mid);
    assert_eq!(&a, &[3, 4, 5, 6, 7, 1, 2]);
    let k = a.len() - mid;
    a.rotate(k);
    assert_eq!(&a, &[1, 2, 3, 4, 5, 6, 7]);

    use std::ops::Range;
    fn slide<T>(slice: &mut [T], range: Range<usize>, to: usize) {
        if to < range.start {
            slice[to..range.end].rotate(range.start-to);
        } else if to > range.end {
            slice[range.start..to].rotate(range.end-range.start);
        }
    }
    let mut v: Vec<_> = (0..10).collect();
    slide(&mut v, 1..4, 7);
    assert_eq!(&v, &[0, 4, 5, 6, 1, 2, 3, 7, 8, 9]);
    slide(&mut v, 6..8, 1);
    assert_eq!(&v, &[0, 3, 7, 4, 5, 6, 1, 2, 8, 9]);Run

#### `fn clone_from_slice(&mut self, src: &[T]) where
T: Clone,`
1.7.0

Copies the elements from `src` into `self`.

The length of `src` must be the same as `self`.

If `src` implements `Copy`, it can be more performant to use `copy_from_slice`.

# Panics

This function will panic if the two slices have different lengths.

# Example

    let mut dst = [0, 0, 0];
    let src = [1, 2, 3];

    dst.clone_from_slice(&src);
    assert!(dst == [1, 2, 3]);Run

#### `fn copy_from_slice(&mut self, src: &[T]) where
T: Copy,`
1.9.0

Copies all elements from `src` into `self`, using a memcpy.

The length of `src` must be the same as `self`.

If `src` does not implement `Copy`, use `clone_from_slice`.

# Panics

This function will panic if the two slices have different lengths.

# Example

    let mut dst = [0, 0, 0];
    let src = [1, 2, 3];

    dst.copy_from_slice(&src);
    assert_eq!(src, dst);Run

#### `fn to_vec(&self) -> Vec<T> where
T: Clone,`

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

## Trait Implementations

### `impl<T> Eq for Vec<T> where
T: Eq,`
[src]

### `impl<T> Default for Vec<T>`
[src]

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

Creates an empty `Vec<T>`.

### `impl<T> PartialOrd<Vec<T>> for Vec<T> where
T: PartialOrd<T>,`
[src]

Implements comparison of vectors, lexicographically.

#### `fn partial_cmp(&self, other: &Vec<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> Extend<T> for Vec<T>`
[src]

#### `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 Vec<T> where
T: 'a + Copy,`
1.2.0
[src]

#### `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> IndexMut<Range<usize>> for Vec<T>`
[src]

#### `fn index_mut(&mut self, index: Range<usize>) -> &mut [T]`

The method for the mutable indexing (`container[index]`) operation

### `impl<T> IndexMut<RangeFrom<usize>> for Vec<T>`
[src]

#### `fn index_mut(&mut self, index: RangeFrom<usize>) -> &mut [T]`

The method for the mutable indexing (`container[index]`) operation

### `impl<T> IndexMut<RangeToInclusive<usize>> for Vec<T>`
[src]

#### `fn index_mut(&mut self, index: RangeToInclusive<usize>) -> &mut [T]`

The method for the mutable indexing (`container[index]`) operation

### `impl<T> IndexMut<usize> for Vec<T>`
[src]

#### `fn index_mut(&mut self, index: usize) -> &mut T`

The method for the mutable indexing (`container[index]`) operation

### `impl<T> IndexMut<RangeInclusive<usize>> for Vec<T>`
[src]

#### `fn index_mut(&mut self, index: RangeInclusive<usize>) -> &mut [T]`

The method for the mutable indexing (`container[index]`) operation

### `impl<T> IndexMut<RangeFull> for Vec<T>`
[src]

#### `fn index_mut(&mut self, _index: RangeFull) -> &mut [T]`

The method for the mutable indexing (`container[index]`) operation

### `impl<T> IndexMut<RangeTo<usize>> for Vec<T>`
[src]

#### `fn index_mut(&mut self, index: RangeTo<usize>) -> &mut [T]`

The method for the mutable indexing (`container[index]`) operation

### `impl<T> BorrowMut<[T]> for Vec<T>`
[src]

#### `fn borrow_mut(&mut self) -> &mut [T]`

Mutably borrows from an owned value. Read more

### `impl<'a, T> IntoIterator for &'a mut Vec<T>`
[src]

#### `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<'a, T> IntoIterator for &'a Vec<T>`
[src]

#### `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<T> IntoIterator for Vec<T>`
[src]

#### `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>`

Creates a consuming iterator, that is, one that moves each value out of the vector (from start to end). The vector cannot be used after calling this.

# Examples

    let v = vec!["a".to_string(), "b".to_string()];
    for s in v.into_iter() {
        // s has type String, not &String
        println!("{}", s);
    }Run

### `impl<T> Borrow<[T]> for Vec<T>`
[src]

#### `fn borrow(&self) -> &[T]`

Immutably borrows from an owned value. Read more

### `impl<T> Hash for Vec<T> where
T: Hash,`
[src]

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

Feeds this value into the given [`Hasher`]. Read more

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

Feeds a slice of this type into the given [`Hasher`]. Read more

### `impl<T> Ord for Vec<T> where
T: Ord,`
[src]

Implements ordering of vectors, lexicographically.

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

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

#### `fn max(self, other: Self) -> Self`

🔬 This is a nightly-only experimental API. (`ord_max_min` #25663)

Compares and returns the maximum of two values. Read more

#### `fn min(self, other: Self) -> Self`

🔬 This is a nightly-only experimental API. (`ord_max_min` #25663)

Compares and returns the minimum of two values. Read more

### `impl<T> DerefMut for Vec<T>`
[src]

#### `fn deref_mut(&mut self) -> &mut [T]`

The method called to mutably dereference a value

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

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

Returns a copy of the value. Read more

#### `fn clone_from(&mut self, other: &Vec<T>)`

Performs copy-assignment from `source`. Read more

### `impl<T> Deref for Vec<T>`
[src]

#### `type Target = [T]`

The resulting type after dereferencing

#### `fn deref(&self) -> &[T]`

The method called to dereference a value

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 25]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 25]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 25]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 12]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 12]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 12]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 18]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 18]) -> bool`

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

#### `fn ne(&self, other: &[B; 18]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b mut [B]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b mut [B]) -> bool`

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

#### `fn ne(&self, other: &&'b mut [B]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 17]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 17]) -> bool`

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

#### `fn ne(&self, other: &[B; 17]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 27]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 27]) -> bool`

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

#### `fn ne(&self, other: &[B; 27]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 25]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 25]) -> bool`

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

#### `fn ne(&self, other: &[B; 25]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 23]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 23]) -> bool`

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

#### `fn ne(&self, other: &[B; 23]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 0]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 0]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 0]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 1]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 1]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 1]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 1]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 1]) -> bool`

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

#### `fn ne(&self, other: &[B; 1]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 19]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 19]) -> bool`

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

#### `fn ne(&self, other: &[B; 19]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 32]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 32]) -> bool`

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

#### `fn ne(&self, other: &[B; 32]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 8]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 8]) -> bool`

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

#### `fn ne(&self, other: &[B; 8]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 28]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 28]) -> bool`

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

#### `fn ne(&self, other: &[B; 28]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 31]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 31]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 31]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 28]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 28]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 28]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 0]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 0]) -> bool`

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

#### `fn ne(&self, other: &[B; 0]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B]) -> bool`

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

#### `fn ne(&self, other: &&'b [B]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 4]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 4]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 4]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 13]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 13]) -> bool`

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

#### `fn ne(&self, other: &[B; 13]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 26]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 26]) -> bool`

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

#### `fn ne(&self, other: &[B; 26]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 16]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 16]) -> bool`

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

#### `fn ne(&self, other: &[B; 16]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 3]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 3]) -> bool`

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

#### `fn ne(&self, other: &[B; 3]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 20]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 20]) -> bool`

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

#### `fn ne(&self, other: &[B; 20]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 11]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 11]) -> bool`

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

#### `fn ne(&self, other: &[B; 11]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 10]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 10]) -> bool`

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

#### `fn ne(&self, other: &[B; 10]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 29]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 29]) -> bool`

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

#### `fn ne(&self, other: &[B; 29]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 23]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 23]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 23]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 6]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 6]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 6]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 10]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 10]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 10]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 24]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 24]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 24]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 13]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 13]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 13]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 2]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 2]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 2]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 8]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 8]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 8]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 29]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 29]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 29]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<Vec<B>> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &Vec<B>) -> bool`

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

#### `fn ne(&self, other: &Vec<B>) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 32]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 32]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 32]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 26]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 26]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 26]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 11]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 11]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 11]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 15]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 15]) -> bool`

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

#### `fn ne(&self, other: &[B; 15]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 31]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 31]) -> bool`

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

#### `fn ne(&self, other: &[B; 31]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 5]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 5]) -> bool`

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

#### `fn ne(&self, other: &[B; 5]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 21]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 21]) -> bool`

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

#### `fn ne(&self, other: &[B; 21]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 24]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 24]) -> bool`

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

#### `fn ne(&self, other: &[B; 24]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 18]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 18]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 18]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 30]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 30]) -> bool`

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

#### `fn ne(&self, other: &[B; 30]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 2]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 2]) -> bool`

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

#### `fn ne(&self, other: &[B; 2]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 9]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 9]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 9]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 22]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 22]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 22]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 15]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 15]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 15]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 9]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 9]) -> bool`

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

#### `fn ne(&self, other: &[B; 9]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 19]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 19]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 19]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 7]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 7]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 7]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 4]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 4]) -> bool`

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

#### `fn ne(&self, other: &[B; 4]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 27]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 27]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 27]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 12]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 12]) -> bool`

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

#### `fn ne(&self, other: &[B; 12]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 5]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 5]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 5]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 20]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 20]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 20]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 22]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 22]) -> bool`

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

#### `fn ne(&self, other: &[B; 22]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 3]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 3]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 3]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 7]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 7]) -> bool`

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

#### `fn ne(&self, other: &[B; 7]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 30]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 30]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 30]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 16]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 16]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 16]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 21]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 21]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 21]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 14]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 14]) -> bool`

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

#### `fn ne(&self, other: &[B; 14]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 14]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 14]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 14]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<[B; 6]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &[B; 6]) -> bool`

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

#### `fn ne(&self, other: &[B; 6]) -> bool`

This method tests for `!=`.

### `impl<'a, 'b, A, B> PartialEq<&'b [B; 17]> for Vec<A> where
A: PartialEq<B>,`
[src]

#### `fn eq(&self, other: &&'b [B; 17]) -> bool`

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

#### `fn ne(&self, other: &&'b [B; 17]) -> bool`

This method tests for `!=`.

### `impl<T> AsMut<Vec<T>> for Vec<T>`
1.5.0
[src]

#### `fn as_mut(&mut self) -> &mut Vec<T>`

Performs the conversion.

### `impl<T> AsMut<[T]> for Vec<T>`
1.5.0
[src]

#### `fn as_mut(&mut self) -> &mut [T]`

Performs the conversion.

### `impl<T> Drop for Vec<T>`
[src]

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

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

### `impl<'a, T> From<&'a [T]> for Vec<T> where
T: Clone,`
[src]

#### `fn from(s: &'a [T]) -> Vec<T>`

Performs the conversion.

### `impl<'a, T> From<&'a mut [T]> for Vec<T> where
T: Clone,`
1.19.0
[src]

#### `fn from(s: &'a mut [T]) -> Vec<T>`

Performs the conversion.

### `impl<T> From<Box<[T]>> for Vec<T>`
1.18.0
[src]

#### `fn from(s: Box<[T]>) -> Vec<T>`

Performs the conversion.

### `impl<T> From<BinaryHeap<T>> for Vec<T>`
1.5.0
[src]

#### `fn from(heap: BinaryHeap<T>) -> Vec<T>`

Performs the conversion.

### `impl<T> From<VecDeque<T>> for Vec<T>`
1.10.0
[src]

#### `fn from(other: VecDeque<T>) -> Vec<T>`

Performs the conversion.

### `impl<'a, T> From<Cow<'a, [T]>> for Vec<T> where
[T]: ToOwned,
<[T] as ToOwned>::Owned == Vec<T>,`
1.14.0
[src]

#### `fn from(s: Cow<'a, [T]>) -> Vec<T>`

Performs the conversion.

### `impl<'a> From<&'a str> for Vec<u8>`
[src]

#### `fn from(s: &'a str) -> Vec<u8>`

Performs the conversion.

### `impl From<String> for Vec<u8>`
1.14.0
[src]

#### `fn from(string: String) -> Vec<u8>`

Performs the conversion.

### `impl<T> Index<RangeFrom<usize>> for Vec<T>`
[src]

#### `type Output = [T]`

The returned type after indexing

#### `fn index(&self, index: RangeFrom<usize>) -> &[T]`

The method for the indexing (`container[index]`) operation

### `impl<T> Index<RangeFull> for Vec<T>`
[src]

#### `type Output = [T]`

The returned type after indexing

#### `fn index(&self, _index: RangeFull) -> &[T]`

The method for the indexing (`container[index]`) operation

### `impl<T> Index<RangeInclusive<usize>> for Vec<T>`
[src]

#### `type Output = [T]`

The returned type after indexing

#### `fn index(&self, index: RangeInclusive<usize>) -> &[T]`

The method for the indexing (`container[index]`) operation

### `impl<T> Index<usize> for Vec<T>`
[src]

#### `type Output = T`

The returned type after indexing

#### `fn index(&self, index: usize) -> &T`

The method for the indexing (`container[index]`) operation

### `impl<T> Index<RangeTo<usize>> for Vec<T>`
[src]

#### `type Output = [T]`

The returned type after indexing

#### `fn index(&self, index: RangeTo<usize>) -> &[T]`

The method for the indexing (`container[index]`) operation

### `impl<T> Index<RangeToInclusive<usize>> for Vec<T>`
[src]

#### `type Output = [T]`

The returned type after indexing

#### `fn index(&self, index: RangeToInclusive<usize>) -> &[T]`

The method for the indexing (`container[index]`) operation

### `impl<T> Index<Range<usize>> for Vec<T>`
[src]

#### `type Output = [T]`

The returned type after indexing

#### `fn index(&self, index: Range<usize>) -> &[T]`

The method for the indexing (`container[index]`) operation

### `impl<T> FromIterator<T> for Vec<T>`
[src]

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

Creates a value from an iterator. Read more

### `impl<T> AsRef<Vec<T>> for Vec<T>`
[src]

#### `fn as_ref(&self) -> &Vec<T>`

Performs the conversion.

### `impl<T> AsRef<[T]> for Vec<T>`
[src]

#### `fn as_ref(&self) -> &[T]`

Performs the conversion.

### `impl<T> Debug for Vec<T> where
T: Debug,`
[src]

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

Formats the value using the given formatter.

### `impl From<CString> for Vec<u8>`
1.7.0
[src]

#### `fn from(s: CString) -> Vec<u8>`

Performs the conversion.

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

Write is implemented for `Vec<u8>` by appending to the vector. The vector will grow as needed.

#### `fn write(&mut self, buf: &[u8]) -> Result<usize>`

Write a buffer into this object, returning how many bytes were written. Read more

#### `fn write_all(&mut self, buf: &[u8]) -> Result<()>`

Attempts to write an entire buffer into this write. Read more

#### `fn flush(&mut self) -> Result<()>`

Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more

#### `fn write_fmt(&mut self, fmt: Arguments) -> Result<()>`

Writes a formatted string into this writer, returning any error encountered. Read more

#### `fn by_ref(&mut self) -> &mut Self where
Self: Sized,`

Creates a "by reference" adaptor for this instance of `Write`. Read more

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