Struct arrayvec::ArrayVec

pub struct ArrayVec<A: Array> {
    // some fields omitted
}

A vector with a fixed capacity.

The ArrayVec is a vector backed by a fixed size array. It keeps track of the number of initialized elements.

The vector is a contiguous value that you can store directly on the stack if needed.

It offers a simple API but also dereferences to a slice, so that the full slice API is available.

ArrayVec can be converted into a by value iterator.

Methods

impl<A: Array> ArrayVec<A>

fn new() -> ArrayVec<A>

Create a new empty ArrayVec.

Capacity is inferred from the type parameter.

use arrayvec::ArrayVec;

let mut array = ArrayVec::<[_; 16]>::new();
array.push(1);
array.push(2);
assert_eq!(&array[..], &[1, 2]);
assert_eq!(array.capacity(), 16);

fn len(&self) -> usize

Return the number of elements in the ArrayVec.

use arrayvec::ArrayVec;

let mut array = ArrayVec::from([1, 2, 3]);
array.pop();
assert_eq!(array.len(), 2);

fn capacity(&self) -> usize

Return the capacity of the ArrayVec.

use arrayvec::ArrayVec;

let array = ArrayVec::from([1, 2, 3]);
assert_eq!(array.capacity(), 3);

fn push(&mut self, element: A::Item) -> Option<A::Item>

Push element to the end of the vector.

Return None if the push succeeds, or and return Some( element ) if the vector is full.

use arrayvec::ArrayVec;

let mut array = ArrayVec::<[_; 2]>::new();

array.push(1);
array.push(2);
let overflow = array.push(3);

assert_eq!(&array[..], &[1, 2]);
assert_eq!(overflow, Some(3));

fn insert(&mut self, index: usize, element: A::Item) -> Option<A::Item>

Insert element in position index.

Shift up all elements after index. If any is pushed out, it is returned.

Return None if no element is shifted out.

use arrayvec::ArrayVec;

let mut array = ArrayVec::<[_; 2]>::new();

assert_eq!(array.insert(0, "x"), None);
assert_eq!(array.insert(0, "y"), None);
assert_eq!(array.insert(0, "z"), Some("x"));
assert_eq!(array.insert(1, "w"), Some("y"));
assert_eq!(&array[..], &["z", "w"]);

fn pop(&mut self) -> Option<A::Item>

Remove the last element in the vector.

Return Some( element ) if the vector is non-empty, else None.

use arrayvec::ArrayVec;

let mut array = ArrayVec::<[_; 2]>::new();

array.push(1);

assert_eq!(array.pop(), Some(1));
assert_eq!(array.pop(), None);

fn swap_remove(&mut self, index: usize) -> Option<A::Item>

Remove the element at index and swap the last element into its place.

This operation is O(1).

Return Some( element ) if the index is in bounds, else None.

use arrayvec::ArrayVec;

let mut array = ArrayVec::from([1, 2, 3]);

assert_eq!(array.swap_remove(0), Some(1));
assert_eq!(&array[..], &[3, 2]);

assert_eq!(array.swap_remove(10), None);

fn remove(&mut self, index: usize) -> Option<A::Item>

Remove the element at index and shift down the following elements.

Return Some( element ) if the index is in bounds, else None.

use arrayvec::ArrayVec;

let mut array = ArrayVec::from([1, 2, 3]);

assert_eq!(array.remove(0), Some(1));
assert_eq!(&array[..], &[2, 3]);

assert_eq!(array.remove(10), None);

fn clear(&mut self)

Remove all elements in the vector.

fn retain<F>(&mut self, f: F) where F: FnMut(&mut A::Item) -> bool

Retains only the elements specified by the predicate.

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

use arrayvec::ArrayVec;

let mut array = ArrayVec::from([1, 2, 3, 4]);
array.retain(|x| *x & 1 != 0 );
assert_eq!(&array[..], &[1, 3]);

unsafe fn set_len(&mut self, length: usize)

Set the vector's length without dropping or moving out elements

May panic if length is greater than the capacity.

This function is unsafe because it changes the notion of the number of “valid” elements in the vector. Use with care.

fn drain<R: RangeArgument>(&mut self, range: R) -> Drain<A>

Create a draining iterator that removes the specified range in the vector and yields the removed items from start to end. The element range is removed even if the iterator is not consumed until the end.

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

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

use arrayvec::ArrayVec;

let mut v = ArrayVec::from([1, 2, 3]);
let u: Vec<_> = v.drain(0..2).collect();
assert_eq!(&v[..], &[3]);
assert_eq!(&u[..], &[1, 2]);

fn into_inner(self) -> Result<A, Self>

Return the inner fixed size array, if it is full to its capacity.

Return an Ok value with the array if length equals capacity, return an Err with self otherwise.

Note: This function may incur unproportionally large overhead to move the array out, its performance is not optimal.

fn dispose(self)

Dispose of self without the overwriting that is needed in Drop.

fn as_slice(&self) -> &[A::Item]

Return a slice containing all elements of the vector.

fn as_mut_slice(&mut self) -> &mut [A::Item]

Return a mutable slice containing all elements of the vector.

Methods from Deref<Target=[A::Item]>

fn len(&self) -> usize

Returns the number of elements in the slice.

Example

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

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());

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

Returns the first element of a 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());

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

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

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

Returns the first and all the rest of the elements of a slice.

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

Returns the first and all the rest of the elements of a slice.

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

Returns the last and all the rest of the elements of a slice.

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

Returns the last and all the rest of the elements of a slice.

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

Returns the last element of a 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());

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

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

fn get(&self, index: usize) -> Option<&T>

Returns the element of a slice at the given index, or None if the index is out of bounds.

Examples

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

fn get_mut(&mut self, index: usize) -> Option<&mut T>

Returns a mutable reference to the element at the given index, or None if the index is out of bounds

unsafe fn get_unchecked(&self, index: usize) -> &T

Returns a pointer to the element at the given index, without doing bounds checking.

unsafe fn get_unchecked_mut(&mut self, index: usize) -> &mut T

Returns an unsafe mutable pointer to the element in index

fn as_ptr(&self) -> *const T

Returns an 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 slice may cause its buffer to be reallocated, which would also make any pointers to it invalid.

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 slice may cause its buffer to be reallocated, which would also make any pointers to it invalid.

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

Swaps two elements in a 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.

Example

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

fn reverse(&mut self)

Reverse the order of elements in a slice, in place.

Example

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

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

Returns an iterator over the slice.

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

Returns an iterator that allows modifying each value

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

Print the adjacent pairs of a slice (i.e. [1,2], [2,3], [3,4]):

let v = &[1, 2, 3, 4];
for win in v.windows(2) {
    println!("{:?}", win);
}

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

Print the slice two elements at a time (i.e. [1,2], [3,4], [5]):

let v = &[1, 2, 3, 4, 5];
for win in v.chunks(2) {
    println!("{:?}", win);
}

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.

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);

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.

Example

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 == []);
}

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

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

let v = [10, 40, 30, 20, 60, 50];
for group in v.split(|num| *num % 3 == 0) {
    println!("{:?}", group);
}

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.

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);
}

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.

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);
}

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.

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));

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]));

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]));

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

Binary search a 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, });

fn binary_search_by<F>(&self, f: F) -> Result<usize, usize> where F: FnMut(&T) -> Ordering

Binary search a 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, });

fn sort(&mut self) where T: Ord

Sorts the slice, in place.

This is equivalent to self.sort_by(|a, b| a.cmp(b)).

This is a stable sort.

Examples

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

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

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

Sorts the slice, in place, using key to extract a key by which to order the sort by.

This sort is O(n log n) worst-case and stable, but allocates approximately 2 * n, where n is the length of self.

This is a stable sort.

Examples

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

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

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

Sorts the slice, in place, using compare to compare elements.

This sort is O(n log n) worst-case and stable, but allocates approximately 2 * n, where n is the length of self.

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]);

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

Copies the elements from src into self.

The length of this slice must be the same as the slice passed in.

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]);

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

Unstable (copy_from_slice)

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

The length of src must be the same as self.

Panics

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

Example

#![feature(copy_from_slice)]
let mut dst = [0, 0, 0];
let src = [1, 2, 3];

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

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

Copies self into a new Vec.

fn into_vec(self: Box<[T]>) -> Vec<T>

Converts self into a vector without clones or allocation.

Trait Implementations

impl<A: Array> Drop for ArrayVec<A>

fn drop(&mut self)

impl<A: Array> Deref for ArrayVec<A>

type Target = [A::Item]

fn deref(&self) -> &[A::Item]

impl<A: Array> DerefMut for ArrayVec<A>

fn deref_mut(&mut self) -> &mut [A::Item]

impl<A: Array> From<A> for ArrayVec<A>

Create an ArrayVec from an array.

use arrayvec::ArrayVec;

let mut array = ArrayVec::from([1, 2, 3]);
assert_eq!(array.len(), 3);
assert_eq!(array.capacity(), 3);

fn from(array: A) -> Self

impl<'a, A: Array> IntoIterator for &'a ArrayVec<A>

Iterate the ArrayVec with references to each element.

use arrayvec::ArrayVec;

let array = ArrayVec::from([1, 2, 3]);

for elt in &array {
    // ...
}

type Item = &'a A::Item

type IntoIter = Iter<'a, A::Item>

fn into_iter(self) -> Self::IntoIter

impl<'a, A: Array> IntoIterator for &'a mut ArrayVec<A>

Iterate the ArrayVec with mutable references to each element.

use arrayvec::ArrayVec;

let mut array = ArrayVec::from([1, 2, 3]);

for elt in &mut array {
    // ...
}

type Item = &'a mut A::Item

type IntoIter = IterMut<'a, A::Item>

fn into_iter(self) -> Self::IntoIter

impl<A: Array> IntoIterator for ArrayVec<A>

Iterate the ArrayVec with each element by value.

The vector is consumed by this operation.

use arrayvec::ArrayVec;

for elt in ArrayVec::from([1, 2, 3]) {
    // ...
}

type Item = A::Item

type IntoIter = IntoIter<A>

fn into_iter(self) -> IntoIter<A>

impl<A: Array> Extend<A::Item> for ArrayVec<A>

Extend the ArrayVec with an iterator.

Does not extract more items than there is space for. No error occurs if there are more iterator elements.

fn extend<T: IntoIterator<Item=A::Item>>(&mut self, iter: T)

impl<A: Array> FromIterator<A::Item> for ArrayVec<A>

Create an ArrayVec from an iterator.

Does not extract more items than there is space for. No error occurs if there are more iterator elements.

fn from_iter<T: IntoIterator<Item=A::Item>>(iter: T) -> Self

impl<A: Array> Clone for ArrayVec<A> where A::Item: Clone

fn clone(&self) -> Self

fn clone_from(&mut self, rhs: &Self)

impl<A: Array> Hash for ArrayVec<A> where A::Item: Hash

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

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

impl<A: Array> PartialEq for ArrayVec<A> where A::Item: PartialEq

fn eq(&self, other: &Self) -> bool

fn ne(&self, other: &Rhs) -> bool

impl<A: Array> PartialEq<[A::Item]> for ArrayVec<A> where A::Item: PartialEq

fn eq(&self, other: &[A::Item]) -> bool

fn ne(&self, other: &Rhs) -> bool

impl<A: Array> Eq for ArrayVec<A> where A::Item: Eq

impl<A: Array> Borrow<[A::Item]> for ArrayVec<A>

fn borrow(&self) -> &[A::Item]

impl<A: Array> BorrowMut<[A::Item]> for ArrayVec<A>

fn borrow_mut(&mut self) -> &mut [A::Item]

impl<A: Array> AsRef<[A::Item]> for ArrayVec<A>

fn as_ref(&self) -> &[A::Item]

impl<A: Array> AsMut<[A::Item]> for ArrayVec<A>

fn as_mut(&mut self) -> &mut [A::Item]

impl<A: Array> Debug for ArrayVec<A> where A::Item: Debug

fn fmt(&self, f: &mut Formatter) -> Result

impl<A: Array> Default for ArrayVec<A>

fn default() -> ArrayVec<A>

impl<A: Array> PartialOrd for ArrayVec<A> where A::Item: PartialOrd

fn partial_cmp(&self, other: &ArrayVec<A>) -> Option<Ordering>

fn lt(&self, other: &Self) -> bool

fn le(&self, other: &Self) -> bool

fn ge(&self, other: &Self) -> bool

fn gt(&self, other: &Self) -> bool

impl<A: Array> Ord for ArrayVec<A> where A::Item: Ord

fn cmp(&self, other: &ArrayVec<A>) -> Ordering

impl<A: Array<Item=u8>> Write for ArrayVec<A>

Write appends written data to the end of the vector.

Requires features="std".

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

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

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

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

fn by_ref(&mut self) -> &mut Self

fn broadcast<W>(self, other: W) -> Broadcast<Self, W> where W: Write