Struct arrayvec::ArrayVec

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pub struct ArrayVec<T, const CAP: usize> { /* private fields */ }
Expand description

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 ArrayVec<T, CAP> is parameterized by T for the element type and CAP for the maximum capacity.

CAP is of type usize but is range limited to u32::MAX; attempting to create larger arrayvecs with larger capacity will panic.

The vector is a contiguous value (storing the elements inline) 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. The ArrayVec can be converted into a by value iterator.

Implementations

Create a new empty ArrayVec.

The maximum capacity is given by the generic parameter CAP.

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);

Create a new empty ArrayVec (const fn).

The maximum capacity is given by the generic parameter CAP.

use arrayvec::ArrayVec;

static ARRAY: ArrayVec<u8, 1024> = ArrayVec::new_const();

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);

Returns whether the ArrayVec is empty.

use arrayvec::ArrayVec;

let mut array = ArrayVec::from([1]);
array.pop();
assert_eq!(array.is_empty(), true);

Return the capacity of the ArrayVec.

use arrayvec::ArrayVec;

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

Return true if the ArrayVec is completely filled to its capacity, false otherwise.

use arrayvec::ArrayVec;

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

Returns the capacity left in the ArrayVec.

use arrayvec::ArrayVec;

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

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]);

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());

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]);

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]);

Remove all elements in the vector.

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 if the array is full or the index is out of bounds. See try_insert 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"]);

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"]);

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);

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]);

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);

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]);

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());

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]);

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 length is not greater than the capacity.

Copy all elements from the slice and append to the ArrayVec.

use arrayvec::ArrayVec;

let mut vec: ArrayVec<usize, 10> = ArrayVec::new();
vec.push(1);
vec.try_extend_from_slice(&[2, 3]).unwrap();
assert_eq!(&vec[..], &[1, 2, 3]);
Errors

This method will return an error if the capacity left (see remaining_capacity) is smaller then the length of the provided slice.

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 v1 = ArrayVec::from([1, 2, 3]);
let v2: ArrayVec<_, 3> = v1.drain(0..2).collect();
assert_eq!(&v1[..], &[3]);
assert_eq!(&v2[..], &[1, 2]);

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.

Return the inner fixed size array.

Safety: This operation is safe if and only if length equals capacity.

Returns the ArrayVec, replacing the original with a new empty ArrayVec.

use arrayvec::ArrayVec;

let mut v = ArrayVec::from([0, 1, 2, 3]);
assert_eq!([0, 1, 2, 3], v.take().into_inner().unwrap());
assert!(v.is_empty());

Return a slice containing all elements of the vector.

Return a mutable slice containing all elements of the vector.

Return a raw pointer to the vector’s buffer.

Return a raw mutable pointer to the vector’s buffer.

Trait Implementations

Performs the conversion.

Performs the conversion.

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

Return an empty array

The resulting type after dereferencing.

Dereferences the value.

Mutably dereferences the value.

Executes the destructor for this type. Read more

Extend the ArrayVec with an iterator.

Panics if extending the vector exceeds its capacity.

Extend the ArrayVec with an iterator.

Panics if extending the vector exceeds its capacity.

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

Extends a collection with exactly one element.

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

Reserves capacity in a collection for the given number of additional elements. Read more

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);

Performs the conversion.

Create an ArrayVec from an iterator.

Panics if the number of elements in the iterator exceeds the arrayvec’s capacity.

Create an ArrayVec from an iterator.

Panics if the number of elements in the iterator exceeds the arrayvec’s capacity.

Feeds this value into the given Hasher. Read more

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

Iterate the ArrayVec with references to each element.

use arrayvec::ArrayVec;

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

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

The type of the elements being iterated over.

Which kind of iterator are we turning this into?

Creates an iterator from a value. Read more

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 {
    // ...
}

The type of the elements being iterated over.

Which kind of iterator are we turning this into?

Creates an iterator from a value. Read more

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]) {
    // ...
}

The type of the elements being iterated over.

Which kind of iterator are we turning this into?

Creates an iterator from a value. Read more

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

Restrict a value to a certain interval. Read more

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

This method tests for !=.

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

This method tests for !=.

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 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

Try to create an ArrayVec from a slice. This will return an error if the slice was too big to fit.

use arrayvec::ArrayVec;
use std::convert::TryInto as _;

let array: ArrayVec<_, 4> = (&[1, 2, 3] as &[_]).try_into().unwrap();
assert_eq!(array.len(), 3);
assert_eq!(array.capacity(), 4);

The type returned in the event of a conversion error.

Performs the conversion.

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.