1.0.0[][src]Struct std::collections::btree_map::Keys

pub struct Keys<'a, K, V> where
    K: 'a + 'a,
    V: 'a + 'a, 
{ /* fields omitted */ }

An iterator over the keys of a BTreeMap.

This struct is created by the keys method on BTreeMap. See its documentation for more.

Trait Implementations

impl<'_, K, V> FusedIterator for Keys<'_, K, V>1.26.0[src]

impl<'_, K, V> ExactSizeIterator for Keys<'_, K, V>[src]

fn is_empty(&self) -> bool[src]

🔬 This is a nightly-only experimental API. (exact_size_is_empty #35428)

Returns true if the iterator is empty. Read more

impl<'a, K, V> Iterator for Keys<'a, K, V>[src]

type Item = &'a K

The type of the elements being iterated over.

fn count(self) -> usize[src]

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

fn last(self) -> Option<Self::Item>[src]

Consumes the iterator, returning the last element. Read more

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

Returns the nth element of the iterator. Read more

Important traits for StepBy<I>
fn step_by(self, step: usize) -> StepBy<Self>1.28.0[src]

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

Important traits for Chain<A, B>
fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter> where
    U: IntoIterator<Item = Self::Item>, 
[src]

Takes two iterators and creates a new iterator over both in sequence. Read more

Important traits for Zip<A, B>
fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter> where
    U: IntoIterator
[src]

'Zips up' two iterators into a single iterator of pairs. Read more

Important traits for Map<I, F>
fn map<B, F>(self, f: F) -> Map<Self, F> where
    F: FnMut(Self::Item) -> B, 
[src]

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

fn for_each<F>(self, f: F) where
    F: FnMut(Self::Item), 
1.21.0[src]

Calls a closure on each element of an iterator. Read more

Important traits for Filter<I, P>
fn filter<P>(self, predicate: P) -> Filter<Self, P> where
    P: FnMut(&Self::Item) -> bool
[src]

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

Important traits for FilterMap<I, F>
fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F> where
    F: FnMut(Self::Item) -> Option<B>, 
[src]

Creates an iterator that both filters and maps. Read more

Important traits for Enumerate<I>
fn enumerate(self) -> Enumerate<Self>[src]

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

Important traits for Peekable<I>
fn peekable(self) -> Peekable<Self>[src]

Creates an iterator which can use peek to look at the next element of the iterator without consuming it. Read more

Important traits for SkipWhile<I, P>
fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P> where
    P: FnMut(&Self::Item) -> bool
[src]

Creates an iterator that [skip]s elements based on a predicate. Read more

Important traits for TakeWhile<I, P>
fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P> where
    P: FnMut(&Self::Item) -> bool
[src]

Creates an iterator that yields elements based on a predicate. Read more

Important traits for Skip<I>
fn skip(self, n: usize) -> Skip<Self>[src]

Creates an iterator that skips the first n elements. Read more

Important traits for Take<I>
fn take(self, n: usize) -> Take<Self>[src]

Creates an iterator that yields its first n elements. Read more

Important traits for Scan<I, St, F>
fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F> where
    F: FnMut(&mut St, Self::Item) -> Option<B>, 
[src]

An iterator adaptor similar to [fold] that holds internal state and produces a new iterator. Read more

Important traits for FlatMap<I, U, F>
fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F> where
    F: FnMut(Self::Item) -> U,
    U: IntoIterator
[src]

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

Important traits for Flatten<I>
fn flatten(self) -> Flatten<Self> where
    Self::Item: IntoIterator
1.29.0[src]

Creates an iterator that flattens nested structure. Read more

Important traits for Fuse<I>
fn fuse(self) -> Fuse<Self>[src]

Creates an iterator which ends after the first [None]. Read more

Important traits for Inspect<I, F>
fn inspect<F>(self, f: F) -> Inspect<Self, F> where
    F: FnMut(&Self::Item), 
[src]

Do something with each element of an iterator, passing the value on. Read more

Important traits for &'_ mut F
fn by_ref(&mut self) -> &mut Self[src]

Borrows an iterator, rather than consuming it. Read more

#[must_use = "if you really need to exhaust the iterator, consider `.for_each(drop)` instead"] fn collect<B>(self) -> B where
    B: FromIterator<Self::Item>, 
[src]

Transforms an iterator into a collection. Read more

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

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

fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
    F: FnMut(B, Self::Item) -> R,
    R: Try<Ok = B>, 
1.27.0[src]

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

fn try_for_each<F, R>(&mut self, f: F) -> R where
    F: FnMut(Self::Item) -> R,
    R: Try<Ok = ()>, 
1.27.0[src]

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

fn fold<B, F>(self, init: B, f: F) -> B where
    F: FnMut(B, Self::Item) -> B, 
[src]

An iterator method that applies a function, producing a single, final value. Read more

fn all<F>(&mut self, f: F) -> bool where
    F: FnMut(Self::Item) -> bool
[src]

Tests if every element of the iterator matches a predicate. Read more

fn any<F>(&mut self, f: F) -> bool where
    F: FnMut(Self::Item) -> bool
[src]

Tests if any element of the iterator matches a predicate. Read more

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

Searches for an element of an iterator that satisfies a predicate. Read more

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

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

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

Searches for an element in an iterator, returning its index. Read more

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

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

fn max(self) -> Option<Self::Item> where
    Self::Item: Ord
[src]

Returns the maximum element of an iterator. Read more

fn min(self) -> Option<Self::Item> where
    Self::Item: Ord
[src]

Returns the minimum element of an iterator. Read more

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

Returns the element that gives the maximum value from the specified function. Read more

fn max_by<F>(self, compare: F) -> Option<Self::Item> where
    F: FnMut(&Self::Item, &Self::Item) -> Ordering
1.15.0[src]

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

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

Returns the element that gives the minimum value from the specified function. Read more

fn min_by<F>(self, compare: F) -> Option<Self::Item> where
    F: FnMut(&Self::Item, &Self::Item) -> Ordering
1.15.0[src]

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

Important traits for Rev<I>
fn rev(self) -> Rev<Self> where
    Self: DoubleEndedIterator
[src]

Reverses an iterator's direction. Read more

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

Converts an iterator of pairs into a pair of containers. Read more

Important traits for Copied<I>
fn copied<'a, T>(self) -> Copied<Self> where
    Self: Iterator<Item = &'a T>,
    T: 'a + Copy
1.36.0[src]

Creates an iterator which copies all of its elements. Read more

Important traits for Cloned<I>
fn cloned<'a, T>(self) -> Cloned<Self> where
    Self: Iterator<Item = &'a T>,
    T: 'a + Clone
[src]

Creates an iterator which [clone]s all of its elements. Read more

Important traits for Cycle<I>
fn cycle(self) -> Cycle<Self> where
    Self: Clone
[src]

Repeats an iterator endlessly. Read more

fn sum<S>(self) -> S where
    S: Sum<Self::Item>, 
1.11.0[src]

Sums the elements of an iterator. Read more

fn product<P>(self) -> P where
    P: Product<Self::Item>, 
1.11.0[src]

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

fn cmp<I>(self, other: I) -> Ordering where
    I: IntoIterator<Item = Self::Item>,
    Self::Item: Ord
1.5.0[src]

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

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

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

fn eq<I>(self, other: I) -> bool where
    I: IntoIterator,
    Self::Item: PartialEq<<I as IntoIterator>::Item>, 
1.5.0[src]

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

fn ne<I>(self, other: I) -> bool where
    I: IntoIterator,
    Self::Item: PartialEq<<I as IntoIterator>::Item>, 
1.5.0[src]

Determines if the elements of this Iterator are unequal to those of another. Read more

fn lt<I>(self, other: I) -> bool where
    I: IntoIterator,
    Self::Item: PartialOrd<<I as IntoIterator>::Item>, 
1.5.0[src]

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

fn le<I>(self, other: I) -> bool where
    I: IntoIterator,
    Self::Item: PartialOrd<<I as IntoIterator>::Item>, 
1.5.0[src]

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

fn gt<I>(self, other: I) -> bool where
    I: IntoIterator,
    Self::Item: PartialOrd<<I as IntoIterator>::Item>, 
1.5.0[src]

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

fn ge<I>(self, other: I) -> bool where
    I: IntoIterator,
    Self::Item: PartialOrd<<I as IntoIterator>::Item>, 
1.5.0[src]

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

fn is_sorted(self) -> bool where
    Self::Item: PartialOrd<Self::Item>, 
[src]

🔬 This is a nightly-only experimental API. (is_sorted #53485)

new API

Checks if the elements of this iterator are sorted. Read more

fn is_sorted_by<F>(self, compare: F) -> bool where
    F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>, 
[src]

🔬 This is a nightly-only experimental API. (is_sorted #53485)

new API

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

fn is_sorted_by_key<F, K>(self, f: F) -> bool where
    F: FnMut(&Self::Item) -> K,
    K: PartialOrd<K>, 
[src]

🔬 This is a nightly-only experimental API. (is_sorted #53485)

new API

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

impl<'_, K, V> Clone for Keys<'_, K, V>[src]

fn clone_from(&mut self, source: &Self)[src]

Performs copy-assignment from source. Read more

impl<'_, K, V> Debug for Keys<'_, K, V> where
    K: Debug
1.17.0[src]

impl<'a, K, V> DoubleEndedIterator for Keys<'a, K, V>[src]

fn nth_back(&mut self, n: usize) -> Option<Self::Item>1.37.0[src]

Returns the nth element from the end of the iterator. Read more

fn try_rfold<B, F, R>(&mut self, init: B, f: F) -> R where
    F: FnMut(B, Self::Item) -> R,
    R: Try<Ok = B>, 
1.27.0[src]

This is the reverse version of [try_fold()]: it takes elements starting from the back of the iterator. Read more

fn rfold<B, F>(self, accum: B, f: F) -> B where
    F: FnMut(B, Self::Item) -> B, 
1.27.0[src]

An iterator method that reduces the iterator's elements to a single, final value, starting from the back. Read more

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

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

Auto Trait Implementations

impl<'a, K, V> Send for Keys<'a, K, V> where
    K: Sync,
    V: Sync

impl<'a, K, V> Sync for Keys<'a, K, V> where
    K: Sync,
    V: Sync

Blanket Implementations

impl<T, U> TryFrom<U> for T where
    U: Into<T>, 
[src]

type Error = Infallible

The type returned in the event of a conversion error.

impl<I> IntoIterator for I where
    I: Iterator
[src]

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?

impl<T, U> Into<U> for T where
    U: From<T>, 
[src]

impl<T> From<T> for T[src]

impl<T, U> TryInto<U> for T where
    U: TryFrom<T>, 
[src]

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

The type returned in the event of a conversion error.

impl<T> Borrow<T> for T where
    T: ?Sized
[src]

impl<T> BorrowMut<T> for T where
    T: ?Sized
[src]

impl<T> Any for T where
    T: 'static + ?Sized
[src]

impl<T> ToOwned for T where
    T: Clone
[src]

type Owned = T

The resulting type after obtaining ownership.