Struct drain_filter_polyfill::DrainFilter

pub struct DrainFilter<'a, T, F>where
    F: FnMut(&mut T) -> bool,{ /* private fields */ }

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

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

Example

use drain_filter_polyfill::VecExt;

let mut v = vec![0, 1, 2];
let iter: drain_filter_polyfill::DrainFilter<_, _> = v.drain_filter(|x| *x % 2 == 0);

Implementations

impl<T, F> DrainFilter<'_, T, F>where
F: FnMut(&mut T) -> bool,

pub fn keep_rest(self)

Keep unyielded elements in the source Vec.

Examples

use drain_filter_polyfill::VecExt;

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

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']);

Trait Implementations

impl<'a, T: Debug, F> Debug for DrainFilter<'a, T, F>where
F: FnMut(&mut T) -> bool + Debug,

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

Formats the value using the given formatter.

impl<T, F> Drop for DrainFilter<'_, T, F>where
F: FnMut(&mut T) -> bool,

fn drop(&mut self)

Executes the destructor for this type.

impl<T, F> Iterator for DrainFilter<'_, T, F>where
F: FnMut(&mut T) -> bool,

type Item = T

The type of the elements being iterated over.

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

Advances the iterator and returns the next value.

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

Returns the bounds on the remaining length of the iterator.

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)

Advances the iterator and returns an array containing the next N values.

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

Consumes the iterator, counting the number of iterations and returning it.

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

Consumes the iterator, returning the last element.

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

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

Advances the iterator by n elements.

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

Returns the nth element of the iterator.

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.

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.

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.

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)

Creates a new iterator which places an item generated by separator between adjacent items of the original iterator.

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.

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

Calls a closure on each element of an iterator.

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.

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.

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

Creates an iterator which gives the current iteration count as well as the next value.

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.

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.

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.

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.

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

Creates an iterator that skips the first n elements.

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.

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.

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.

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

Creates an iterator which ends after the first None.

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.

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

Borrows an iterator, rather than consuming it.

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

Transforms an iterator into a collection.

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)

Collects all the items from an iterator into a collection.

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.

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)

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.

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.

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.

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.

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.

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)

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.

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.

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.

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.

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.

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)

Applies function to the elements of iterator and returns the first true result or the first error.

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.

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.

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.

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.

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.

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.

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.

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.

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

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

Returns an iterator over N elements of the iterator at a time.

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

Sums the elements of an iterator.

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

Iterates over the entire iterator, multiplying all the elements

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)

Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function.

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

Lexicographically compares the elements of this Iterator with those of another.

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)

Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function.

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.

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)

Determines if the elements of this Iterator are equal to those of another with respect to the specified equality function.

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 unequal to those of another.

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.

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.

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.

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.

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)

Checks if the elements of this iterator are sorted using the given comparator function.

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

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

Checks if the elements of this iterator are sorted using the given key extraction function.