Struct std::vec::Drain

1.6.0 · source ·
pub struct Drain<'a, T, A = Global>where
    T: 'a,
    A: Allocator + 'a,{ /* private fields */ }
Expand description

A draining iterator for Vec<T>.

This struct is created by Vec::drain. See its documentation for more.

§Example

let mut v = vec![0, 1, 2];
let iter: std::vec::Drain<'_, _> = v.drain(..);
Run

Implementations§

source§

impl<T, A> Drain<'_, T, A>where A: Allocator,

This impl block contains no items.

Private helper methods for Splice::drop

source§

impl<'a, T, A> Drain<'a, T, A>where A: Allocator,

1.46.0 · source

pub fn as_slice(&self) -> &[T]

Returns the remaining items of this iterator as a slice.

§Examples
let mut vec = vec!['a', 'b', 'c'];
let mut drain = vec.drain(..);
assert_eq!(drain.as_slice(), &['a', 'b', 'c']);
let _ = drain.next().unwrap();
assert_eq!(drain.as_slice(), &['b', 'c']);
Run
source

pub fn allocator(&self) -> &A

🔬This is a nightly-only experimental API. (allocator_api #32838)

Returns a reference to the underlying allocator.

source

pub fn keep_rest(self)

🔬This is a nightly-only experimental API. (drain_keep_rest #101122)

Keep unyielded elements in the source Vec.

§Examples
#![feature(drain_keep_rest)]

let mut vec = vec!['a', 'b', 'c'];
let mut drain = vec.drain(..);

assert_eq!(drain.next().unwrap(), 'a');

// This call keeps 'b' and 'c' in the vec.
drain.keep_rest();

// If we wouldn't call `keep_rest()`,
// `vec` would be empty.
assert_eq!(vec, ['b', 'c']);
Run

Trait Implementations§

1.46.0 · source§

impl<'a, T, A> AsRef<[T]> for Drain<'a, T, A>where A: Allocator,

source§

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

Converts this type into a shared reference of the (usually inferred) input type.
1.17.0 · source§

impl<T, A> Debug for Drain<'_, T, A>where T: Debug, A: Allocator,

source§

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

Formats the value using the given formatter. Read more
source§

impl<T, A> DoubleEndedIterator for Drain<'_, T, A>where A: Allocator,

source§

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

Removes and returns an element from the end of the iterator. Read more
source§

fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize>

🔬This is a nightly-only experimental API. (iter_advance_by #77404)
Advances the iterator from the back by n elements. Read more
1.37.0 · source§

fn nth_back(&mut self, n: usize) -> Option<Self::Item>

Returns the nth element from the end of the iterator. Read more
1.27.0 · source§

fn try_rfold<B, F, R>(&mut self, init: B, f: F) -> Rwhere Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Output = B>,

This is the reverse version of Iterator::try_fold(): it takes elements starting from the back of the iterator. Read more
1.27.0 · source§

fn rfold<B, F>(self, init: B, f: F) -> Bwhere Self: Sized, F: FnMut(B, Self::Item) -> B,

An iterator method that reduces the iterator’s elements to a single, final value, starting from the back. Read more
1.27.0 · source§

fn rfind<P>(&mut self, predicate: P) -> Option<Self::Item>where Self: Sized, P: FnMut(&Self::Item) -> bool,

Searches for an element of an iterator from the back that satisfies a predicate. Read more
source§

impl<T, A> Drop for Drain<'_, T, A>where A: Allocator,

source§

fn drop(&mut self)

Executes the destructor for this type. Read more
source§

impl<T, A> ExactSizeIterator for Drain<'_, T, A>where A: Allocator,

source§

fn is_empty(&self) -> bool

🔬This is a nightly-only experimental API. (exact_size_is_empty #35428)
Returns true if the iterator is empty. Read more
1.0.0 · source§

fn len(&self) -> usize

Returns the exact remaining length of the iterator. Read more
source§

impl<T, A> Iterator for Drain<'_, T, A>where A: Allocator,

§

type Item = T

The type of the elements being iterated over.
source§

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

Advances the iterator and returns the next value. Read more
source§

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the iterator. Read more
source§

fn next_chunk<const N: usize>( &mut self ) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>where Self: Sized,

🔬This is a nightly-only experimental API. (iter_next_chunk #98326)
Advances the iterator and returns an array containing the next N values. Read more
1.0.0 · source§

fn count(self) -> usizewhere Self: Sized,

Consumes the iterator, counting the number of iterations and returning it. Read more
1.0.0 · source§

fn last(self) -> Option<Self::Item>where Self: Sized,

Consumes the iterator, returning the last element. Read more
source§

fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize>

🔬This is a nightly-only experimental API. (iter_advance_by #77404)
Advances the iterator by n elements. Read more
1.0.0 · source§

fn nth(&mut self, n: usize) -> Option<Self::Item>

Returns the nth element of the iterator. Read more
1.28.0 · source§

fn step_by(self, step: usize) -> StepBy<Self> where Self: Sized,

Creates an iterator starting at the same point, but stepping by the given amount at each iteration. Read more
1.0.0 · source§

fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter> where Self: Sized, U: IntoIterator<Item = Self::Item>,

Takes two iterators and creates a new iterator over both in sequence. Read more
1.0.0 · source§

fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter> where Self: Sized, U: IntoIterator,

‘Zips up’ two iterators into a single iterator of pairs. Read more
source§

fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G> where Self: Sized, G: FnMut() -> Self::Item,

🔬This is a nightly-only experimental API. (iter_intersperse #79524)
Creates a new iterator which places an item generated by separator between adjacent items of the original iterator. Read more
1.0.0 · source§

fn map<B, F>(self, f: F) -> Map<Self, F> where Self: Sized, F: FnMut(Self::Item) -> B,

Takes a closure and creates an iterator which calls that closure on each element. Read more
1.21.0 · source§

fn for_each<F>(self, f: F)where Self: Sized, F: FnMut(Self::Item),

Calls a closure on each element of an iterator. Read more
1.0.0 · source§

fn filter<P>(self, predicate: P) -> Filter<Self, P> where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator which uses a closure to determine if an element should be yielded. Read more
1.0.0 · source§

fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F> where Self: Sized, F: FnMut(Self::Item) -> Option<B>,

Creates an iterator that both filters and maps. Read more
1.0.0 · source§

fn enumerate(self) -> Enumerate<Self> where Self: Sized,

Creates an iterator which gives the current iteration count as well as the next value. Read more
1.0.0 · source§

fn peekable(self) -> Peekable<Self> where Self: Sized,

Creates an iterator which can use the peek and peek_mut methods to look at the next element of the iterator without consuming it. See their documentation for more information. Read more
1.0.0 · source§

fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P> where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator that skips elements based on a predicate. Read more
1.0.0 · source§

fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P> where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator that yields elements based on a predicate. Read more
1.57.0 · source§

fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P> where Self: Sized, P: FnMut(Self::Item) -> Option<B>,

Creates an iterator that both yields elements based on a predicate and maps. Read more
1.0.0 · source§

fn skip(self, n: usize) -> Skip<Self> where Self: Sized,

Creates an iterator that skips the first n elements. Read more
1.0.0 · source§

fn take(self, n: usize) -> Take<Self> where Self: Sized,

Creates an iterator that yields the first n elements, or fewer if the underlying iterator ends sooner. Read more
1.0.0 · source§

fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F> where Self: Sized, F: FnMut(&mut St, Self::Item) -> Option<B>,

An iterator adapter which, like fold, holds internal state, but unlike fold, produces a new iterator. Read more
1.0.0 · source§

fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F> where Self: Sized, U: IntoIterator, F: FnMut(Self::Item) -> U,

Creates an iterator that works like map, but flattens nested structure. Read more
source§

fn map_windows<F, R, const N: usize>(self, f: F) -> MapWindows<Self, F, N> where Self: Sized, F: FnMut(&[Self::Item; N]) -> R,

🔬This is a nightly-only experimental API. (iter_map_windows #87155)
Calls the given function f for each contiguous window of size N over self and returns an iterator over the outputs of f. Like slice::windows(), the windows during mapping overlap as well. Read more
1.0.0 · source§

fn fuse(self) -> Fuse<Self> where Self: Sized,

Creates an iterator which ends after the first None. Read more
1.0.0 · source§

fn inspect<F>(self, f: F) -> Inspect<Self, F> where Self: Sized, F: FnMut(&Self::Item),

Does something with each element of an iterator, passing the value on. Read more
1.0.0 · source§

fn by_ref(&mut self) -> &mut Selfwhere Self: Sized,

Borrows an iterator, rather than consuming it. Read more
1.0.0 · source§

fn collect<B>(self) -> Bwhere B: FromIterator<Self::Item>, Self: Sized,

Transforms an iterator into a collection. Read more
source§

fn collect_into<E>(self, collection: &mut E) -> &mut Ewhere E: Extend<Self::Item>, Self: Sized,

🔬This is a nightly-only experimental API. (iter_collect_into #94780)
Collects all the items from an iterator into a collection. Read more
1.0.0 · source§

fn partition<B, F>(self, f: F) -> (B, B)where Self: Sized, B: Default + Extend<Self::Item>, F: FnMut(&Self::Item) -> bool,

Consumes an iterator, creating two collections from it. Read more
source§

fn partition_in_place<'a, T, P>(self, predicate: P) -> usizewhere T: 'a, Self: Sized + DoubleEndedIterator<Item = &'a mut T>, P: FnMut(&T) -> bool,

🔬This is a nightly-only experimental API. (iter_partition_in_place #62543)
Reorders the elements of this iterator in-place according to the given predicate, such that all those that return true precede all those that return false. Returns the number of true elements found. Read more
source§

fn is_partitioned<P>(self, predicate: P) -> boolwhere Self: Sized, P: FnMut(Self::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_is_partitioned #62544)
Checks if the elements of this iterator are partitioned according to the given predicate, such that all those that return true precede all those that return false. Read more
1.27.0 · source§

fn try_fold<B, F, R>(&mut self, init: B, f: F) -> Rwhere Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Output = B>,

An iterator method that applies a function as long as it returns successfully, producing a single, final value. Read more
1.27.0 · source§

fn try_for_each<F, R>(&mut self, f: F) -> Rwhere Self: Sized, F: FnMut(Self::Item) -> R, R: Try<Output = ()>,

An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error. Read more
1.0.0 · source§

fn fold<B, F>(self, init: B, f: F) -> Bwhere Self: Sized, F: FnMut(B, Self::Item) -> B,

Folds every element into an accumulator by applying an operation, returning the final result. Read more
1.51.0 · source§

fn reduce<F>(self, f: F) -> Option<Self::Item>where Self: Sized, F: FnMut(Self::Item, Self::Item) -> Self::Item,

Reduces the elements to a single one, by repeatedly applying a reducing operation. Read more
source§

fn try_reduce<F, R>( &mut self, f: F ) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryTypewhere Self: Sized, F: FnMut(Self::Item, Self::Item) -> R, R: Try<Output = Self::Item>, <R as Try>::Residual: Residual<Option<Self::Item>>,

🔬This is a nightly-only experimental API. (iterator_try_reduce #87053)
Reduces the elements to a single one by repeatedly applying a reducing operation. If the closure returns a failure, the failure is propagated back to the caller immediately. Read more
1.0.0 · source§

fn all<F>(&mut self, f: F) -> boolwhere Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if every element of the iterator matches a predicate. Read more
1.0.0 · source§

fn any<F>(&mut self, f: F) -> boolwhere Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if any element of the iterator matches a predicate. Read more
1.0.0 · source§

fn find<P>(&mut self, predicate: P) -> Option<Self::Item>where Self: Sized, P: FnMut(&Self::Item) -> bool,

Searches for an element of an iterator that satisfies a predicate. Read more
1.30.0 · source§

fn find_map<B, F>(&mut self, f: F) -> Option<B>where Self: Sized, F: FnMut(Self::Item) -> Option<B>,

Applies function to the elements of iterator and returns the first non-none result. Read more
source§

fn try_find<F, R>( &mut self, f: F ) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryTypewhere Self: Sized, F: FnMut(&Self::Item) -> R, R: Try<Output = bool>, <R as Try>::Residual: Residual<Option<Self::Item>>,

🔬This is a nightly-only experimental API. (try_find #63178)
Applies function to the elements of iterator and returns the first true result or the first error. Read more
1.0.0 · source§

fn position<P>(&mut self, predicate: P) -> Option<usize>where Self: Sized, P: FnMut(Self::Item) -> bool,

Searches for an element in an iterator, returning its index. Read more
1.0.0 · source§

fn rposition<P>(&mut self, predicate: P) -> Option<usize>where P: FnMut(Self::Item) -> bool, Self: Sized + ExactSizeIterator + DoubleEndedIterator,

Searches for an element in an iterator from the right, returning its index. Read more
source§

fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the maximum value from the specified function. Read more
1.15.0 · source§

fn max_by<F>(self, compare: F) -> Option<Self::Item>where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the maximum value with respect to the specified comparison function. Read more
source§

fn min_by_key<B, F>(self, f: F) -> Option<Self::Item>where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the minimum value from the specified function. Read more
1.15.0 · source§

fn min_by<F>(self, compare: F) -> Option<Self::Item>where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the minimum value with respect to the specified comparison function. Read more
1.0.0 · source§

fn rev(self) -> Rev<Self> where Self: Sized + DoubleEndedIterator,

Reverses an iterator’s direction. Read more
1.0.0 · source§

fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)where FromA: Default + Extend<A>, FromB: Default + Extend<B>, Self: Sized + Iterator<Item = (A, B)>,

Converts an iterator of pairs into a pair of containers. Read more
1.36.0 · source§

fn copied<'a, T>(self) -> Copied<Self> where T: 'a + Copy, Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which copies all of its elements. Read more
1.0.0 · source§

fn cloned<'a, T>(self) -> Cloned<Self> where T: 'a + Clone, Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which clones all of its elements. Read more
source§

fn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N> where Self: Sized,

🔬This is a nightly-only experimental API. (iter_array_chunks #100450)
Returns an iterator over N elements of the iterator at a time. Read more
1.11.0 · source§

fn sum<S>(self) -> Swhere Self: Sized, S: Sum<Self::Item>,

Sums the elements of an iterator. Read more
1.11.0 · source§

fn product<P>(self) -> Pwhere Self: Sized, P: Product<Self::Item>,

Iterates over the entire iterator, multiplying all the elements Read more
source§

fn cmp_by<I, F>(self, other: I, cmp: F) -> Orderingwhere Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,

🔬This is a nightly-only experimental API. (iter_order_by #64295)
Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function. Read more
1.5.0 · source§

fn partial_cmp<I>(self, other: I) -> Option<Ordering>where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Lexicographically compares the PartialOrd elements of this Iterator with those of another. The comparison works like short-circuit evaluation, returning a result without comparing the remaining elements. As soon as an order can be determined, the evaluation stops and a result is returned. Read more
source§

fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering>where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,

🔬This is a nightly-only experimental API. (iter_order_by #64295)
Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function. Read more
1.5.0 · source§

fn eq<I>(self, other: I) -> boolwhere I: IntoIterator, Self::Item: PartialEq<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are equal to those of another. Read more
source§

fn eq_by<I, F>(self, other: I, eq: F) -> boolwhere Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_order_by #64295)
Determines if the elements of this Iterator are equal to those of another with respect to the specified equality function. Read more
1.5.0 · source§

fn ne<I>(self, other: I) -> boolwhere I: IntoIterator, Self::Item: PartialEq<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are not equal to those of another. Read more
1.5.0 · source§

fn lt<I>(self, other: I) -> boolwhere I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically less than those of another. Read more
1.5.0 · source§

fn le<I>(self, other: I) -> boolwhere I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically less or equal to those of another. Read more
1.5.0 · source§

fn gt<I>(self, other: I) -> boolwhere I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically greater than those of another. Read more
1.5.0 · source§

fn ge<I>(self, other: I) -> boolwhere I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically greater than or equal to those of another. Read more
source§

fn is_sorted_by<F>(self, compare: F) -> boolwhere Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,

🔬This is a nightly-only experimental API. (is_sorted #53485)
Checks if the elements of this iterator are sorted using the given comparator function. Read more
source§

fn is_sorted_by_key<F, K>(self, f: F) -> boolwhere Self: Sized, F: FnMut(Self::Item) -> K, K: PartialOrd,

🔬This is a nightly-only experimental API. (is_sorted #53485)
Checks if the elements of this iterator are sorted using the given key extraction function. Read more
1.26.0 · source§

impl<T, A> FusedIterator for Drain<'_, T, A>where A: Allocator,

source§

impl<T, A> Send for Drain<'_, T, A>where T: Send, A: Send + Allocator,

source§

impl<T, A> Sync for Drain<'_, T, A>where T: Sync, A: Sync + Allocator,

source§

impl<T, A> TrustedLen for Drain<'_, T, A>where A: Allocator,

Auto Trait Implementations§

§

impl<'a, T, A> RefUnwindSafe for Drain<'a, T, A>where A: RefUnwindSafe, T: RefUnwindSafe,

§

impl<'a, T, A> Unpin for Drain<'a, T, A>

§

impl<'a, T, A> UnwindSafe for Drain<'a, T, A>where A: RefUnwindSafe, T: RefUnwindSafe,

Blanket Implementations§

source§

impl<T> Any for Twhere T: 'static + ?Sized,

source§

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
source§

impl<T> Borrow<T> for Twhere T: ?Sized,

source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
source§

impl<T> BorrowMut<T> for Twhere T: ?Sized,

source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
source§

impl<T> From<T> for T

source§

fn from(t: T) -> T

Returns the argument unchanged.

source§

impl<T, U> Into<U> for Twhere U: From<T>,

source§

fn into(self) -> U

Calls U::from(self).

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

source§

impl<I> IntoIterator for Iwhere I: Iterator,

§

type Item = <I as Iterator>::Item

The type of the elements being iterated over.
§

type IntoIter = I

Which kind of iterator are we turning this into?
const: unstable · source§

fn into_iter(self) -> I

Creates an iterator from a value. Read more
source§

impl<T, U> TryFrom<U> for Twhere U: Into<T>,

§

type Error = Infallible

The type returned in the event of a conversion error.
source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
source§

impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

§

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.