Struct nom::lib::std::vec::Vec1.0.0[−][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]);

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]);

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]);

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);
}

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'

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!

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;

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 very subtle — if you intend to allocate memory using a Vec and use it for something else (either to pass to unsafe code, or to build your own memory-backed collection), be sure to deallocate this memory by using from_raw_parts to recover the Vec and then 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, contiguous elements in order (what you would see if you coerced it to a slice), followed by capacity-len logically uninitialized, contiguous elements.

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

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]

ⓘImportant traits for Vec<u8>

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();

ⓘImportant traits for Vec<u8>

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 although the returned vector has the capacity specified, the vector will have a zero length. 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);

ⓘImportant traits for Vec<u8>

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).
  • ptr's T needs to have the same size and alignment as it was allocated with.
  • 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 data structures. 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]);
    }
}

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);

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);

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);

🔬 This is a nightly-only experimental API. (try_reserve)

new API

Tries to reserve 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.

Errors

If the capacity overflows, or the allocator reports a failure, then an error is returned.

Examples

#![feature(try_reserve)]
use std::collections::CollectionAllocErr;

fn process_data(data: &[u32]) -> Result<Vec<u32>, CollectionAllocErr> {
    let mut output = Vec::new();

    // Pre-reserve the memory, exiting if we can't
    output.try_reserve(data.len())?;

    // Now we know this can't OOM in the middle of our complex work
    output.extend(data.iter().map(|&val| {
        val * 2 + 5 // very complicated
    }));

    Ok(output)
}

🔬 This is a nightly-only experimental API. (try_reserve)

new API

Tries to 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.

Errors

If the capacity overflows, or the allocator reports a failure, then an error is returned.

Examples

#![feature(try_reserve)]
use std::collections::CollectionAllocErr;

fn process_data(data: &[u32]) -> Result<Vec<u32>, CollectionAllocErr> {
    let mut output = Vec::new();

    // Pre-reserve the memory, exiting if we can't
    output.try_reserve(data.len())?;

    // Now we know this can't OOM in the middle of our complex work
    output.extend(data.iter().map(|&val| {
        val * 2 + 5 // very complicated
    }));

    Ok(output)
}

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);

🔬 This is a nightly-only experimental API. (shrink_to)

new API

Shrinks the capacity of the vector with a lower bound.

The capacity will remain at least as large as both the length and the supplied value.

Panics if the current capacity is smaller than the supplied minimum capacity.

Examples

#![feature(shrink_to)]
let mut vec = Vec::with_capacity(10);
vec.extend([1, 2, 3].iter().cloned());
assert_eq!(vec.capacity(), 10);
vec.shrink_to(4);
assert!(vec.capacity() >= 4);
vec.shrink_to(0);
assert!(vec.capacity() >= 3);

ⓘImportant traits for Box<R>

Converts the vector into Box<[T]>.

Note that this will drop any excess capacity.

Examples

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

let slice = v.into_boxed_slice();

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);

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]);

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]);

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

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

ⓘImportant traits for &'a [u8]

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();

ⓘImportant traits for &'a [u8]

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();

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']);

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);
}

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);
}

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"]);

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

Panics

Panics if index > len.

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]);

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]);

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]);

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]);

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

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"]);

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]);

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]);

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, []);

ⓘImportant traits for Drain<'a, T>

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, &[]);

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());

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);

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());

ⓘImportant traits for Vec<u8>

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]);

🔬 This is a nightly-only experimental API. (vec_resize_with)

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 the result of calling the closure f. The return values from f will end up in the Vec in the order they have been generated.

If new_len is less than len, the Vec is simply truncated.

This method uses a closure to create new values on every push. If you'd rather Clone a given value, use resize. If you want to use the [Default] trait to generate values, you can pass [Default::default()] as the second argument..

Examples

#![feature(vec_resize_with)]

let mut vec = vec![1, 2, 3];
vec.resize_with(5, Default::default);
assert_eq!(vec, [1, 2, 3, 0, 0]);

let mut vec = vec![];
let mut p = 1;
vec.resize_with(4, || { p *= 2; p });
assert_eq!(vec, [2, 4, 8, 16]);

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

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 be able clone the passed value. If you need more flexibility (or want to rely on Default instead of Clone), use resize_with.

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]);

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]);

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

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

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]);

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

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]);

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

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]);

impl<T> Vec<T>
[src]

ⓘImportant traits for Splice<'a, I>

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

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]);

ⓘImportant traits for DrainFilter<'a, T, F>

🔬 This is a nightly-only experimental API. (drain_filter)

recently added

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

If the closure returns true, then the element is removed and yielded. If the closure returns false, the element will remain in the vector and will not be yielded by the iterator.

Using this method is equivalent to the following code:

let mut i = 0;
while i != vec.len() {
    if some_predicate(&mut vec[i]) {
        let val = vec.remove(i);
        // your code here
    } else {
        i += 1;
    }
}

But drain_filter is easier to use. drain_filter is also more efficient, because it can backshift the elements of the array in bulk.

Note that drain_filter also lets you mutate every element in the filter closure, regardless of whether you choose to keep or remove it.

Examples

Splitting an array into evens and odds, reusing the original allocation:

#![feature(drain_filter)]
let mut numbers = vec![1, 2, 3, 4, 5, 6, 8, 9, 11, 13, 14, 15];

let evens = numbers.drain_filter(|x| *x % 2 == 0).collect::<Vec<_>>();
let odds = numbers;

assert_eq!(evens, vec![2, 4, 6, 8, 14]);
assert_eq!(odds, vec![1, 3, 5, 9, 11, 13, 15]);

Methods from Deref<Target = [T]>

Returns the number of elements in the slice.

Examples

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

Returns true if the slice has a length of 0.

Examples

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

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());

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]);

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]);
}

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]);

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]);
}

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]);

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());

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]);

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));

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]);

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);
}

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]);

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));
    }
}

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]);

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"]);

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

Examples

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

ⓘImportant traits for Iter<'a, 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);

ⓘImportant traits for IterMut<'a, 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]);

ⓘImportant traits for Windows<'a, 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.

Examples

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

If the slice is shorter than size:

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

ⓘImportant traits for Chunks<'a, T>

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

See exact_chunks for a variant of this iterator that returns chunks of always exactly chunk_size elements.

Panics

Panics if chunk_size is 0.

Examples

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

ⓘImportant traits for ExactChunks<'a, T>

🔬 This is a nightly-only experimental API. (exact_chunks)

Returns an iterator over chunk_size elements of the slice at a time. The chunks are slices and do not overlap. If chunk_size does not divide the length of the slice, then the last up to chunk_size-1 elements will be omitted.

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

Panics

Panics if chunk_size is 0.

Examples

#![feature(exact_chunks)]

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

ⓘImportant traits for ChunksMut<'a, 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.

See exact_chunks_mut for a variant of this iterator that returns chunks of always exactly chunk_size elements.

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]);

ⓘImportant traits for ExactChunksMut<'a, T>

🔬 This is a nightly-only experimental API. (exact_chunks)

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 up to chunk_size-1 elements will be omitted.

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

Panics

Panics if chunk_size is 0.

Examples

#![feature(exact_chunks)]

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

for chunk in v.exact_chunks_mut(2) {
    for elem in chunk.iter_mut() {
        *elem += count;
    }
    count += 1;
}
assert_eq!(v, &[1, 1, 2, 2, 0]);

Divides one slice into two at an index.

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

Panics

Panics if mid > len.

Examples

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

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

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

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

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

ⓘImportant traits for Split<'a, T, P>

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());

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());

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());

ⓘImportant traits for SplitMut<'a, T, P>

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]);

ⓘImportant traits for RSplit<'a, T, P>

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

Examples

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

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

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

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

ⓘImportant traits for RSplitMut<'a, T, P>

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

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]);

ⓘImportant traits for SplitN<'a, T, P>

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);
}

ⓘImportant traits for SplitNMut<'a, T, P>

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]);

ⓘImportant traits for RSplitN<'a, T, P>

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);
}

ⓘImportant traits for RSplitNMut<'a, T, P>

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]);

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));

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]));

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(&[]));

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]));

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(&[]));

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.

Examples

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

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

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

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.

Examples

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

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

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

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, });

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 pattern-defeating quicksort by Orson Peters, which combines the fast average case of randomized quicksort with the fast worst case of heapsort, while achieving linear time on slices with certain patterns. It uses some randomization to avoid degenerate cases, but with a fixed seed to always provide deterministic behavior.

It is typically 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]);

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 pattern-defeating quicksort by Orson Peters, which combines the fast average case of randomized quicksort with the fast worst case of heapsort, while achieving linear time on slices with certain patterns. It uses some randomization to avoid degenerate cases, but with a fixed seed to always provide deterministic behavior.

It is typically 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]);

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(m n log(m n)) worst-case, where the key function is O(m).

Current implementation

The current algorithm is based on pattern-defeating quicksort by Orson Peters, which combines the fast average case of randomized quicksort with the fast worst case of heapsort, while achieving linear time on slices with certain patterns. It uses some randomization to avoid degenerate cases, but with a fixed seed to always provide deterministic behavior.

Examples

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

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

Rotates the slice in-place such that the first mid elements of the slice move to the end while the last self.len() - mid elements move to the front. After calling rotate_left, the element previously at index mid will become the first element in the slice.

Panics

This function will panic if mid is greater than the length of the slice. Note that mid == self.len() does not panic and is a no-op rotation.

Complexity

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

Examples

let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
a.rotate_left(2);
assert_eq!(a, ['c', 'd', 'e', 'f', 'a', 'b']);

Rotating a subslice:

let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
a[1..5].rotate_left(1);
assert_eq!(a, ['a', 'c', 'd', 'e', 'b', 'f']);

Rotates the slice in-place such that the first self.len() - k elements of the slice move to the end while the last k elements move to the front. After calling rotate_right, the element previously at index self.len() - k will become the first element in the slice.

Panics

This function will panic if k is greater than the length of the slice. Note that k == self.len() does not panic and is a no-op rotation.

Complexity

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

Examples

let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
a.rotate_right(2);
assert_eq!(a, ['e', 'f', 'a', 'b', 'c', 'd']);

Rotate a subslice:

let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
a[1..5].rotate_right(1);
assert_eq!(a, ['a', 'e', 'b', 'c', 'd', 'f']);

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.

Examples

Cloning two elements from a slice into another:

let src = [1, 2, 3, 4];
let mut dst = [0, 0];

dst.clone_from_slice(&src[2..]);

assert_eq!(src, [1, 2, 3, 4]);
assert_eq!(dst, [3, 4]);

Rust enforces that there can only be one mutable reference with no immutable references to a particular piece of data in a particular scope. Because of this, attempting to use clone_from_slice on a single slice will result in a compile failure:

ⓘThis example deliberately fails to compile
let mut slice = [1, 2, 3, 4, 5];

slice[..2].clone_from_slice(&slice[3..]); // compile fail!

To work around this, we can use split_at_mut to create two distinct sub-slices from a slice:

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

{
    let (left, right) = slice.split_at_mut(2);
    left.clone_from_slice(&right[1..]);
}

assert_eq!(slice, [4, 5, 3, 4, 5]);

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.

Examples

Copying two elements from a slice into another:

let src = [1, 2, 3, 4];
let mut dst = [0, 0];

dst.copy_from_slice(&src[2..]);

assert_eq!(src, [1, 2, 3, 4]);
assert_eq!(dst, [3, 4]);

Rust enforces that there can only be one mutable reference with no immutable references to a particular piece of data in a particular scope. Because of this, attempting to use copy_from_slice on a single slice will result in a compile failure:

ⓘThis example deliberately fails to compile
let mut slice = [1, 2, 3, 4, 5];

slice[..2].copy_from_slice(&slice[3..]); // compile fail!

To work around this, we can use split_at_mut to create two distinct sub-slices from a slice:

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

{
    let (left, right) = slice.split_at_mut(2);
    left.copy_from_slice(&right[1..]);
}

assert_eq!(slice, [4, 5, 3, 4, 5]);

Swaps all elements in self with those in other.

The length of other must be the same as self.

Panics

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

Example

Swapping two elements across slices:

let mut slice1 = [0, 0];
let mut slice2 = [1, 2, 3, 4];

slice1.swap_with_slice(&mut slice2[2..]);

assert_eq!(slice1, [3, 4]);
assert_eq!(slice2, [1, 2, 0, 0]);

Rust enforces that there can only be one mutable reference to a particular piece of data in a particular scope. Because of this, attempting to use swap_with_slice on a single slice will result in a compile failure:

ⓘThis example deliberately fails to compile
let mut slice = [1, 2, 3, 4, 5];
slice[..2].swap_with_slice(&mut slice[3..]); // compile fail!

To work around this, we can use split_at_mut to create two distinct mutable sub-slices from a slice:

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

{
    let (left, right) = slice.split_at_mut(2);
    left.swap_with_slice(&mut right[1..]);
}

assert_eq!(slice, [4, 5, 3, 1, 2]);

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

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

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

Converts this slice to its ASCII upper case equivalent in-place.

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

To return a new uppercased value without modifying the existing one, use to_ascii_uppercase.

Converts this slice to its ASCII lower case equivalent in-place.

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

To return a new lowercased value without modifying the existing one, use to_ascii_lowercase.

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]);

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]);

Sorts the slice with a key extraction function.

This sort is stable (i.e. does not reorder equal elements) and O(m n log(m n)) worst-case, where the key function is O(m).

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]);

🔬 This is a nightly-only experimental API. (slice_sort_by_cached_key)

Sorts the slice with a key extraction function.

During sorting, the key function is called only once per element.

This sort is stable (i.e. does not reorder equal elements) and O(m n + n log n) worst-case, where the key function is O(m).

For simple key functions (e.g. functions that are property accesses or basic operations), sort_by_key is likely to be faster.

Current implementation

The current algorithm is based on pattern-defeating quicksort by Orson Peters, which combines the fast average case of randomized quicksort with the fast worst case of heapsort, while achieving linear time on slices with certain patterns. It uses some randomization to avoid degenerate cases, but with a fixed seed to always provide deterministic behavior.

In the worst case, the algorithm allocates temporary storage in a Vec<(K, usize)> the length of the slice.

Examples

#![feature(slice_sort_by_cached_key)]
let mut v = [-5i32, 4, 32, -3, 2];

v.sort_by_cached_key(|k| k.to_string());
assert!(v == [-3, -5, 2, 32, 4]);

ⓘImportant traits for Vec<u8>

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.

ⓘImportant traits for Vec<u8>

🔬 This is a nightly-only experimental API. (repeat_generic_slice)

it's on str, why not on slice?

Creates a vector by repeating a slice n times.

Examples

Basic usage:

#![feature(repeat_generic_slice)]

fn main() {
    assert_eq!([1, 2].repeat(3), vec![1, 2, 1, 2, 1, 2]);
}

ⓘImportant traits for Vec<u8>

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

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

To uppercase the value in-place, use make_ascii_uppercase.

ⓘImportant traits for Vec<u8>

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

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

To lowercase the value in-place, use make_ascii_lowercase.

Trait Implementations

impl Write for Vec<u8>
[src]

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

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

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

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

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

ⓘImportant traits for &'a mut R

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

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

ⓘImportant traits for Vec<u8>

Performs the conversion.

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

ⓘImportant traits for &'a [u8]

Performs the conversion.

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

ⓘImportant traits for Vec<u8>

Performs the conversion.

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

ⓘImportant traits for Vec<u8>

Creates an empty Vec<T>.

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

ⓘImportant traits for Vec<u8>

Creates a value from an iterator. Read more

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

Formats the value using the given formatter. Read more

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

ⓘImportant traits for Vec<u8>

Performs the conversion.

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

Performs the conversion.

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

ⓘImportant traits for Vec<u8>

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]

ⓘImportant traits for Vec<u8>

Performs the conversion.

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

ⓘImportant traits for Vec<u8>

Performs the conversion.

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

ⓘImportant traits for Vec<u8>

Performs the conversion.

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

ⓘImportant traits for Vec<u8>

Performs the conversion.

impl<'a, T> From<Vec<T>> for Cow<'a, [T]> where
    T: Clone, 
1.8.0
[src]

Performs the conversion.

impl<T> From<Vec<T>> for BinaryHeap<T> where
    T: Ord, 
1.5.0
[src]

Performs the conversion.

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

ⓘImportant traits for Vec<u8>

Performs the conversion.

impl<T> From<Vec<T>> for Arc<[T]>
1.21.0
[src]

Performs the conversion.

impl<T> From<Vec<T>> for Rc<[T]>
1.21.0
[src]

Performs the conversion.

impl<T> From<Vec<T>> for Box<[T]>
1.20.0
[src]

ⓘImportant traits for Box<R>

Performs the conversion.

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

ⓘImportant traits for Vec<u8>

Performs the conversion.

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

ⓘImportant traits for &'a [u8]

Mutably dereferences the value.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<Vec<B>> for Cow<'a, [A]> where
    A: Clone + PartialEq<B>, 
[src]

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

impl<'a, 'b, A, B> PartialEq<Vec<B>> for VecDeque<A> where
    A: PartialEq<B>, 
1.17.0
[src]

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

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

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

This method tests for !=.

impl<'a, T> Extend<&'a T> for Vec<T> where
    T: 'a + Copy, 
1.2.0
[src]

Extend implementation that copies elements out of references before pushing them onto the Vec.

This implementation is specialized for slice iterators, where it uses copy_from_slice to append the entire slice at once.

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

impl<T> Extend<T> for Vec<T>
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Extends a collection with the contents of an iterator. Read more

impl<T> BorrowMut<[T]> for Vec<T>
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ⓘImportant traits for &'a [u8]

Mutably borrows from an owned value. Read more

impl<T> PartialOrd<Vec<T>> for Vec<T> where
    T: PartialOrd<T>, 
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Implements comparison of vectors, lexicographically.

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

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

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

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

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

impl<T> Deref for Vec<T>
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The resulting type after dereferencing.

ⓘImportant traits for &'a [u8]

Dereferences the value.

impl<T> AsMut<[T]> for Vec<T>
1.5.0
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ⓘImportant traits for &'a [u8]

Performs the conversion.

impl<T> AsMut<Vec<T>> for Vec<T>
1.5.0
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ⓘImportant traits for Vec<u8>

Performs the conversion.

impl<T> Eq for Vec<T> where
    T: Eq, 
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impl<T> Hash for Vec<T> where
    T: Hash, 
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Feeds this value into the given [Hasher]. Read more

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

impl<T> Drop for Vec<T>
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Executes the destructor for this type. Read more

impl<T> Borrow<[T]> for Vec<T>
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ⓘImportant traits for &'a [u8]

Immutably borrows from an owned value. Read more

impl<'a, T> IntoIterator for &'a Vec<T>
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The type of the elements being iterated over.

Which kind of iterator are we turning this into?

ⓘImportant traits for Iter<'a, T>

Creates an iterator from a value. Read more

impl<T> IntoIterator for Vec<T>
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The type of the elements being iterated over.

Which kind of iterator are we turning this into?

ⓘImportant traits for 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);
}

impl<'a, T> IntoIterator for &'a mut Vec<T>
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The type of the elements being iterated over.

Which kind of iterator are we turning this into?

ⓘImportant traits for IterMut<'a, T>

Creates an iterator from a value. Read more

impl<T> Ord for Vec<T> where
    T: Ord, 
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Implements ordering of vectors, lexicographically.

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

Compares and returns the maximum of two values. Read more

Compares and returns the minimum of two values. Read more

impl<T, I> Index<I> for Vec<T> where
    I: SliceIndex<[T]>, 
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The returned type after indexing.

ⓘImportant traits for Vec<u8>

Performs the indexing (container[index]) operation.

impl<T, I> IndexMut<I> for Vec<T> where
    I: SliceIndex<[T]>, 
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ⓘImportant traits for Vec<u8>

Performs the mutable indexing (container[index]) operation.

impl<T> Clone for Vec<T> where
    T: Clone, 
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ⓘImportant traits for Vec<u8>

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Auto Trait Implementations

impl<T> Send for Vec<T> where
    T: Send, 

impl<T> Sync for Vec<T> where
    T: Sync,