Struct serde_json::map::Keys

pub struct Keys<'a> { /* fields omitted */ }

An iterator over a serde_json::Map's keys.

Trait Implementations

impl<'a> Iterator for Keys<'a>

type Item = &'a String

The type of the elements being iterated over.

fn next(&mut self) -> Option<Self::Item>

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 count(self) -> usize

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

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

Consumes the iterator, returning the last element.

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

Returns the nth element of the iterator.

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

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     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     U: IntoIterator,

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

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

Calls a closure on each element of an iterator.

fn filter<P>(self, predicate: P) -> Filter<Self, P> where     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     F: FnMut(Self::Item) -> Option<B>,

Creates an iterator that both filters and maps.

fn enumerate(self) -> Enumerate<Self>

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

fn peekable(self) -> Peekable<Self>

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

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

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

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

Creates an iterator that yields elements based on a predicate.

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

Creates an iterator that skips the first n elements.

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

Creates an iterator that yields its first n elements.

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

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

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

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

fn flatten(self) -> Flatten<Self> where     Self::Item: IntoIterator,

Creates an iterator that flattens nested structure.

fn fuse(self) -> Fuse<Self>

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

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

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

fn by_ref(&mut self) -> &mut Self

Borrows an iterator, rather than consuming it.

#[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>,

Transforms an iterator into a collection.

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

Consumes an iterator, creating two collections from it.

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

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) -> B where     F: FnMut(B, Self::Item) -> B,

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

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

Tests if every element of the iterator matches a predicate.

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

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

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

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

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

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

fn max(self) -> Option<Self::Item> where     Self::Item: Ord,

Returns the maximum element of an iterator.

fn min(self) -> Option<Self::Item> where     Self::Item: Ord,

Returns the minimum element of an iterator.

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

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

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

Reverses an iterator's direction.

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

Converts an iterator of pairs into a pair of containers.

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

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

fn cycle(self) -> Cycle<Self> where     Self: Clone,

Repeats an iterator endlessly.

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

Sums the elements of an iterator.

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

Iterates over the entire iterator, multiplying all the elements

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

impl<'a> ExactSizeIterator for Keys<'a>

fn len(&self) -> usize

Returns the exact number of times the iterator will iterate.

fn is_empty(&self) -> bool

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

Returns whether the iterator is empty.

impl<'a> DoubleEndedIterator for Keys<'a>

fn next_back(&mut self) -> Option<Self::Item>

Removes and returns an element from the end of the iterator.

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

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

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

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

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

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