Struct arrayvec::ArrayVec

pub struct ArrayVec<A: Array> { /* 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>

pub 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);

pub 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);

pub 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);

pub fn is_full(&self) -> bool

Return if the ArrayVec is completely filled.

use arrayvec::ArrayVec;

let mut array = ArrayVec::<[_; 1]>::new();
assert!(!array.is_full());
array.push(1);
assert!(array.is_full());

pub fn push(&mut self, element: A::Item)

Push element to the end of the vector.

Panics if the vector is already full.

use arrayvec::ArrayVec;

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

array.push(1);
array.push(2);

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

pub fn try_push(
    &mut self,
    element: A::Item
) -> Result<(), CapacityError<A::Item>>

Push element to the end of the vector.

Return Ok if the push succeeds, or return an error if the vector is already full.

use arrayvec::ArrayVec;

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

let push1 = array.try_push(1);
let push2 = array.try_push(2);

assert!(push1.is_ok());
assert!(push2.is_ok());

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

let overflow = array.try_push(3);

assert!(overflow.is_err());

pub unsafe fn push_unchecked(&mut self, element: A::Item)

Push element to the end of the vector without checking the capacity.

It is up to the caller to ensure the capacity of the vector is sufficiently large.

This method uses debug assertions to check that the arrayvec is not full.

use arrayvec::ArrayVec;

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

if array.len() + 2 <= array.capacity() {
    unsafe {
        array.push_unchecked(1);
        array.push_unchecked(2);
    }
}

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

pub fn insert(&mut self, index: usize, element: A::Item)

Insert element at position index.

Shift up all elements after index.

It is an error if the index is greater than the length or if the arrayvec is full.

Panics on errors. See try_result for fallible version.

use arrayvec::ArrayVec;

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

array.insert(0, "x");
array.insert(0, "y");
assert_eq!(&array[..], &["y", "x"]);

pub fn try_insert(
    &mut self,
    index: usize,
    element: A::Item
) -> Result<(), CapacityError<A::Item>>

Insert element at position index.

Shift up all elements after index; the index must be less than or equal to the length.

Returns an error if vector is already at full capacity.

Panics index is out of bounds.

use arrayvec::ArrayVec;

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

assert!(array.try_insert(0, "x").is_ok());
assert!(array.try_insert(0, "y").is_ok());
assert!(array.try_insert(0, "z").is_err());
assert_eq!(&array[..], &["y", "x"]);

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

Remove the last element in the vector and return it.

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);

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

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

This operation is O(1).

Return the element if the index is in bounds, else panic.

Panics if the index is out of bounds.

use arrayvec::ArrayVec;

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

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

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

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

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

This is a checked version of .swap_remove.
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_pop(0), Some(1));
assert_eq!(&array[..], &[3, 2]);

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

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

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

The index must be strictly less than the length of the vector.

Panics if the index is out of bounds.

use arrayvec::ArrayVec;

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

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

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

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

This is a checked version of .remove(index). Returns None if there is no element at index. Otherwise, return the element inside Some.

use arrayvec::ArrayVec;

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

assert!(array.pop_at(0).is_some());
assert_eq!(&array[..], &[2, 3]);

assert!(array.pop_at(2).is_none());
assert!(array.pop_at(10).is_none());

pub fn truncate(&mut self, len: usize)

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

If len is greater than the vector’s current length this has no effect.

use arrayvec::ArrayVec;

let mut array = ArrayVec::from([1, 2, 3, 4, 5]);
array.truncate(3);
assert_eq!(&array[..], &[1, 2, 3]);
array.truncate(4);
assert_eq!(&array[..], &[1, 2, 3]);

pub fn clear(&mut self)

Remove all elements in the vector.

pub 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]);

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

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

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

This method uses debug assertions to check that check that length is not greater than the capacity.

Important traits for Drain<'a, A>

impl<'a, A: Array> Iterator for Drain<'a, A> where
    A::Item: 'a,  type Item = A::Item;

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

pub 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.

pub fn dispose(self)

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

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

Return a slice containing all elements of the vector.

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

Return a mutable slice containing all elements of the vector.

Trait Implementations

impl<A: Array> Drop for ArrayVec<A>

fn drop(&mut self)

Executes the destructor for this type.

impl<A: Array> Deref for ArrayVec<A>

type Target = [A::Item]

The resulting type after dereferencing.

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

Dereferences the value.

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

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

Mutably dereferences the value.

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

Performs the conversion.

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

The type of the elements being iterated over.

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

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

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

The type of the elements being iterated over.

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

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

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

The type of the elements being iterated over.

type IntoIter = IntoIter<A>

Which kind of iterator are we turning this into?

Important traits for IntoIter<A>

impl<A: Array> Iterator for IntoIter<A> type Item = A::Item;

fn into_iter(self) -> IntoIter<A>

Creates an iterator from a value.

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)

Extends a collection with the contents of an iterator.

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

Creates a value from an iterator.

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

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

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

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

Feeds this value into the given [Hasher].

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

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

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

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

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

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

This method tests for !=.

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

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

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

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

This method tests for !=.

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]

Immutably borrows from an owned value.

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

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

Mutably borrows from an owned value.

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

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

Performs the conversion.

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

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

Performs the conversion.

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

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

Formats the value using the given formatter.

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

fn default() -> ArrayVec<A>

Return an empty array

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

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

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

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

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

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

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

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

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

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

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

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

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

This method returns an Ordering between self and other.

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

Compares and returns the maximum of two values.

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

Compares and returns the minimum of two values.