pub struct Peekable<I: Iterator> { /* private fields */ }
Expand description
Implementations
sourceimpl<I: Iterator> Peekable<I>
impl<I: Iterator> Peekable<I>
sourcepub fn peek(&mut self) -> Option<&I::Item>
pub fn peek(&mut self) -> Option<&I::Item>
Returns a reference to the next() value without advancing the iterator.
Like next
, if there is a value, it is wrapped in a Some(T)
.
But if the iteration is over, None
is returned.
Because peek()
returns a reference, and many iterators iterate over
references, there can be a possibly confusing situation where the
return value is a double reference. You can see this effect in the
examples below.
Examples
Basic usage:
let xs = [1, 2, 3];
let mut iter = xs.iter().peekable();
// peek() lets us see into the future
assert_eq!(iter.peek(), Some(&&1));
assert_eq!(iter.next(), Some(&1));
assert_eq!(iter.next(), Some(&2));
// The iterator does not advance even if we `peek` multiple times
assert_eq!(iter.peek(), Some(&&3));
assert_eq!(iter.peek(), Some(&&3));
assert_eq!(iter.next(), Some(&3));
// After the iterator is finished, so is `peek()`
assert_eq!(iter.peek(), None);
assert_eq!(iter.next(), None);
Run1.53.0 · sourcepub fn peek_mut(&mut self) -> Option<&mut I::Item>
pub fn peek_mut(&mut self) -> Option<&mut I::Item>
Returns a mutable reference to the next() value without advancing the iterator.
Like next
, if there is a value, it is wrapped in a Some(T)
.
But if the iteration is over, None
is returned.
Because peek_mut()
returns a reference, and many iterators iterate over
references, there can be a possibly confusing situation where the
return value is a double reference. You can see this effect in the examples
below.
Examples
Basic usage:
let mut iter = [1, 2, 3].iter().peekable();
// Like with `peek()`, we can see into the future without advancing the iterator.
assert_eq!(iter.peek_mut(), Some(&mut &1));
assert_eq!(iter.peek_mut(), Some(&mut &1));
assert_eq!(iter.next(), Some(&1));
// Peek into the iterator and set the value behind the mutable reference.
if let Some(p) = iter.peek_mut() {
assert_eq!(*p, &2);
*p = &5;
}
// The value we put in reappears as the iterator continues.
assert_eq!(iter.collect::<Vec<_>>(), vec![&5, &3]);
Run1.51.0 · sourcepub fn next_if(&mut self, func: impl FnOnce(&I::Item) -> bool) -> Option<I::Item>
pub fn next_if(&mut self, func: impl FnOnce(&I::Item) -> bool) -> Option<I::Item>
Consume and return the next value of this iterator if a condition is true.
If func
returns true
for the next value of this iterator, consume and return it.
Otherwise, return None
.
Examples
Consume a number if it’s equal to 0.
let mut iter = (0..5).peekable();
// The first item of the iterator is 0; consume it.
assert_eq!(iter.next_if(|&x| x == 0), Some(0));
// The next item returned is now 1, so `consume` will return `false`.
assert_eq!(iter.next_if(|&x| x == 0), None);
// `next_if` saves the value of the next item if it was not equal to `expected`.
assert_eq!(iter.next(), Some(1));
RunConsume any number less than 10.
let mut iter = (1..20).peekable();
// Consume all numbers less than 10
while iter.next_if(|&x| x < 10).is_some() {}
// The next value returned will be 10
assert_eq!(iter.next(), Some(10));
Run1.51.0 · sourcepub fn next_if_eq<T>(&mut self, expected: &T) -> Option<I::Item> where
T: ?Sized,
I::Item: PartialEq<T>,
pub fn next_if_eq<T>(&mut self, expected: &T) -> Option<I::Item> where
T: ?Sized,
I::Item: PartialEq<T>,
Consume and return the next item if it is equal to expected
.
Example
Consume a number if it’s equal to 0.
let mut iter = (0..5).peekable();
// The first item of the iterator is 0; consume it.
assert_eq!(iter.next_if_eq(&0), Some(0));
// The next item returned is now 1, so `consume` will return `false`.
assert_eq!(iter.next_if_eq(&0), None);
// `next_if_eq` saves the value of the next item if it was not equal to `expected`.
assert_eq!(iter.next(), Some(1));
RunTrait Implementations
1.38.0 · sourceimpl<I> DoubleEndedIterator for Peekable<I> where
I: DoubleEndedIterator,
impl<I> DoubleEndedIterator for Peekable<I> where
I: DoubleEndedIterator,
sourcefn next_back(&mut self) -> Option<Self::Item>
fn next_back(&mut self) -> Option<Self::Item>
Removes and returns an element from the end of the iterator. Read more
sourcefn try_rfold<B, F, R>(&mut self, init: B, f: F) -> R where
Self: Sized,
F: FnMut(B, Self::Item) -> R,
R: Try<Output = B>,
fn try_rfold<B, F, R>(&mut self, init: B, f: F) -> R where
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
sourcefn rfold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, Self::Item) -> Acc,
fn rfold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, Self::Item) -> Acc,
An iterator method that reduces the iterator’s elements to a single, final value, starting from the back. Read more
sourcefn advance_back_by(&mut self, n: usize) -> Result<(), usize>
fn advance_back_by(&mut self, n: usize) -> Result<(), usize>
Advances the iterator from the back by n
elements. Read more
sourceimpl<I: ExactSizeIterator> ExactSizeIterator for Peekable<I>
impl<I: ExactSizeIterator> ExactSizeIterator for Peekable<I>
sourceimpl<I: Iterator> Iterator for Peekable<I>
impl<I: Iterator> Iterator for Peekable<I>
sourcefn next(&mut self) -> Option<I::Item>
fn next(&mut self) -> Option<I::Item>
Advances the iterator and returns the next value. Read more
sourcefn count(self) -> usize
fn count(self) -> usize
Consumes the iterator, counting the number of iterations and returning it. Read more
sourcefn nth(&mut self, n: usize) -> Option<I::Item>
fn nth(&mut self, n: usize) -> Option<I::Item>
Returns the n
th element of the iterator. Read more
sourcefn size_hint(&self) -> (usize, Option<usize>)
fn size_hint(&self) -> (usize, Option<usize>)
Returns the bounds on the remaining length of the iterator. Read more
sourcefn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
Self: Sized,
F: FnMut(B, Self::Item) -> R,
R: Try<Output = B>,
fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
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
sourcefn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, Self::Item) -> Acc,
fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, Self::Item) -> Acc,
Folds every element into an accumulator by applying an operation, returning the final result. Read more
sourcefn next_chunk<const N: usize>(
&mut self
) -> Result<[Self::Item; N], IntoIter<Self::Item, N>> where
Self: Sized,
fn next_chunk<const N: usize>(
&mut self
) -> Result<[Self::Item; N], IntoIter<Self::Item, N>> where
Self: Sized,
Advances the iterator and returns an array containing the next N
values. Read more
sourcefn advance_by(&mut self, n: usize) -> Result<(), usize>
fn advance_by(&mut self, n: usize) -> Result<(), usize>
Advances the iterator by n
elements. Read more
1.28.0 · sourcefn step_by(self, step: usize) -> StepBy<Self>ⓘNotable traits for StepBy<I>impl<I> Iterator for StepBy<I> where
I: Iterator, type Item = I::Item;
where
Self: Sized,
fn step_by(self, step: usize) -> StepBy<Self>ⓘNotable traits for StepBy<I>impl<I> Iterator for StepBy<I> where
I: Iterator, type Item = I::Item;
where
Self: Sized,
I: Iterator, type Item = I::Item;
Creates an iterator starting at the same point, but stepping by the given amount at each iteration. Read more
sourcefn chain<U>(self, other: U) -> Chain<Self, U::IntoIter>ⓘNotable traits for Chain<A, B>impl<A, B> Iterator for Chain<A, B> where
A: Iterator,
B: Iterator<Item = A::Item>, type Item = A::Item;
where
Self: Sized,
U: IntoIterator<Item = Self::Item>,
fn chain<U>(self, other: U) -> Chain<Self, U::IntoIter>ⓘNotable traits for Chain<A, B>impl<A, B> Iterator for Chain<A, B> where
A: Iterator,
B: Iterator<Item = A::Item>, type Item = A::Item;
where
Self: Sized,
U: IntoIterator<Item = Self::Item>,
A: Iterator,
B: Iterator<Item = A::Item>, type Item = A::Item;
Takes two iterators and creates a new iterator over both in sequence. Read more
sourcefn zip<U>(self, other: U) -> Zip<Self, U::IntoIter>ⓘNotable traits for Zip<A, B>impl<A, B> Iterator for Zip<A, B> where
A: Iterator,
B: Iterator, type Item = (A::Item, B::Item);
where
Self: Sized,
U: IntoIterator,
fn zip<U>(self, other: U) -> Zip<Self, U::IntoIter>ⓘNotable traits for Zip<A, B>impl<A, B> Iterator for Zip<A, B> where
A: Iterator,
B: Iterator, type Item = (A::Item, B::Item);
where
Self: Sized,
U: IntoIterator,
A: Iterator,
B: Iterator, type Item = (A::Item, B::Item);
‘Zips up’ two iterators into a single iterator of pairs. Read more
sourcefn intersperse(self, separator: Self::Item) -> Intersperse<Self>ⓘNotable traits for Intersperse<I>impl<I> Iterator for Intersperse<I> where
I: Iterator,
I::Item: Clone, type Item = I::Item;
where
Self: Sized,
Self::Item: Clone,
fn intersperse(self, separator: Self::Item) -> Intersperse<Self>ⓘNotable traits for Intersperse<I>impl<I> Iterator for Intersperse<I> where
I: Iterator,
I::Item: Clone, type Item = I::Item;
where
Self: Sized,
Self::Item: Clone,
I: Iterator,
I::Item: Clone, type Item = I::Item;
Creates a new iterator which places a copy of separator
between adjacent
items of the original iterator. Read more
sourcefn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>ⓘNotable traits for IntersperseWith<I, G>impl<I, G> Iterator for IntersperseWith<I, G> where
I: Iterator,
G: FnMut() -> I::Item, type Item = I::Item;
where
Self: Sized,
G: FnMut() -> Self::Item,
fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>ⓘNotable traits for IntersperseWith<I, G>impl<I, G> Iterator for IntersperseWith<I, G> where
I: Iterator,
G: FnMut() -> I::Item, type Item = I::Item;
where
Self: Sized,
G: FnMut() -> Self::Item,
I: Iterator,
G: FnMut() -> I::Item, type Item = I::Item;
Creates a new iterator which places an item generated by separator
between adjacent items of the original iterator. Read more
sourcefn map<B, F>(self, f: F) -> Map<Self, F>ⓘNotable traits for Map<I, F>impl<B, I: Iterator, F> Iterator for Map<I, F> where
F: FnMut(I::Item) -> B, type Item = B;
where
Self: Sized,
F: FnMut(Self::Item) -> B,
fn map<B, F>(self, f: F) -> Map<Self, F>ⓘNotable traits for Map<I, F>impl<B, I: Iterator, F> Iterator for Map<I, F> where
F: FnMut(I::Item) -> B, type Item = B;
where
Self: Sized,
F: FnMut(Self::Item) -> B,
F: FnMut(I::Item) -> B, type Item = B;
Takes a closure and creates an iterator which calls that closure on each element. Read more
1.21.0 · sourcefn for_each<F>(self, f: F) where
Self: Sized,
F: FnMut(Self::Item),
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
sourcefn filter<P>(self, predicate: P) -> Filter<Self, P>ⓘNotable traits for Filter<I, P>impl<I: Iterator, P> Iterator for Filter<I, P> where
P: FnMut(&I::Item) -> bool, type Item = I::Item;
where
Self: Sized,
P: FnMut(&Self::Item) -> bool,
fn filter<P>(self, predicate: P) -> Filter<Self, P>ⓘNotable traits for Filter<I, P>impl<I: Iterator, P> Iterator for Filter<I, P> where
P: FnMut(&I::Item) -> bool, type Item = I::Item;
where
Self: Sized,
P: FnMut(&Self::Item) -> bool,
P: FnMut(&I::Item) -> bool, type Item = I::Item;
Creates an iterator which uses a closure to determine if an element should be yielded. Read more
sourcefn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>ⓘNotable traits for FilterMap<I, F>impl<B, I: Iterator, F> Iterator for FilterMap<I, F> where
F: FnMut(I::Item) -> Option<B>, type Item = B;
where
Self: Sized,
F: FnMut(Self::Item) -> Option<B>,
fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>ⓘNotable traits for FilterMap<I, F>impl<B, I: Iterator, F> Iterator for FilterMap<I, F> where
F: FnMut(I::Item) -> Option<B>, type Item = B;
where
Self: Sized,
F: FnMut(Self::Item) -> Option<B>,
F: FnMut(I::Item) -> Option<B>, type Item = B;
Creates an iterator that both filters and maps. Read more
sourcefn enumerate(self) -> Enumerate<Self>ⓘNotable traits for Enumerate<I>impl<I> Iterator for Enumerate<I> where
I: Iterator, type Item = (usize, <I as Iterator>::Item);
where
Self: Sized,
fn enumerate(self) -> Enumerate<Self>ⓘNotable traits for Enumerate<I>impl<I> Iterator for Enumerate<I> where
I: Iterator, type Item = (usize, <I as Iterator>::Item);
where
Self: Sized,
I: Iterator, type Item = (usize, <I as Iterator>::Item);
Creates an iterator which gives the current iteration count as well as the next value. Read more
sourcefn peekable(self) -> Peekable<Self>ⓘNotable traits for Peekable<I>impl<I: Iterator> Iterator for Peekable<I> type Item = I::Item;
where
Self: Sized,
fn peekable(self) -> Peekable<Self>ⓘNotable traits for Peekable<I>impl<I: Iterator> Iterator for Peekable<I> type Item = I::Item;
where
Self: Sized,
sourcefn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>ⓘNotable traits for SkipWhile<I, P>impl<I: Iterator, P> Iterator for SkipWhile<I, P> where
P: FnMut(&I::Item) -> bool, type Item = I::Item;
where
Self: Sized,
P: FnMut(&Self::Item) -> bool,
fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>ⓘNotable traits for SkipWhile<I, P>impl<I: Iterator, P> Iterator for SkipWhile<I, P> where
P: FnMut(&I::Item) -> bool, type Item = I::Item;
where
Self: Sized,
P: FnMut(&Self::Item) -> bool,
P: FnMut(&I::Item) -> bool, type Item = I::Item;
sourcefn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>ⓘNotable traits for TakeWhile<I, P>impl<I: Iterator, P> Iterator for TakeWhile<I, P> where
P: FnMut(&I::Item) -> bool, type Item = I::Item;
where
Self: Sized,
P: FnMut(&Self::Item) -> bool,
fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>ⓘNotable traits for TakeWhile<I, P>impl<I: Iterator, P> Iterator for TakeWhile<I, P> where
P: FnMut(&I::Item) -> bool, type Item = I::Item;
where
Self: Sized,
P: FnMut(&Self::Item) -> bool,
P: FnMut(&I::Item) -> bool, type Item = I::Item;
Creates an iterator that yields elements based on a predicate. Read more
1.57.0 · sourcefn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>ⓘNotable traits for MapWhile<I, P>impl<B, I: Iterator, P> Iterator for MapWhile<I, P> where
P: FnMut(I::Item) -> Option<B>, type Item = B;
where
Self: Sized,
P: FnMut(Self::Item) -> Option<B>,
fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>ⓘNotable traits for MapWhile<I, P>impl<B, I: Iterator, P> Iterator for MapWhile<I, P> where
P: FnMut(I::Item) -> Option<B>, type Item = B;
where
Self: Sized,
P: FnMut(Self::Item) -> Option<B>,
P: FnMut(I::Item) -> Option<B>, type Item = B;
Creates an iterator that both yields elements based on a predicate and maps. Read more
sourcefn skip(self, n: usize) -> Skip<Self>ⓘNotable traits for Skip<I>impl<I> Iterator for Skip<I> where
I: Iterator, type Item = <I as Iterator>::Item;
where
Self: Sized,
fn skip(self, n: usize) -> Skip<Self>ⓘNotable traits for Skip<I>impl<I> Iterator for Skip<I> where
I: Iterator, type Item = <I as Iterator>::Item;
where
Self: Sized,
I: Iterator, type Item = <I as Iterator>::Item;
Creates an iterator that skips the first n
elements. Read more
sourcefn take(self, n: usize) -> Take<Self>ⓘNotable traits for Take<I>impl<I> Iterator for Take<I> where
I: Iterator, type Item = <I as Iterator>::Item;
where
Self: Sized,
fn take(self, n: usize) -> Take<Self>ⓘNotable traits for Take<I>impl<I> Iterator for Take<I> where
I: Iterator, type Item = <I as Iterator>::Item;
where
Self: Sized,
I: Iterator, type Item = <I as Iterator>::Item;
Creates an iterator that yields the first n
elements, or fewer
if the underlying iterator ends sooner. Read more
sourcefn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>ⓘNotable traits for Scan<I, St, F>impl<B, I, St, F> Iterator for Scan<I, St, F> where
I: Iterator,
F: FnMut(&mut St, I::Item) -> Option<B>, type Item = B;
where
Self: Sized,
F: FnMut(&mut St, Self::Item) -> Option<B>,
fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>ⓘNotable traits for Scan<I, St, F>impl<B, I, St, F> Iterator for Scan<I, St, F> where
I: Iterator,
F: FnMut(&mut St, I::Item) -> Option<B>, type Item = B;
where
Self: Sized,
F: FnMut(&mut St, Self::Item) -> Option<B>,
I: Iterator,
F: FnMut(&mut St, I::Item) -> Option<B>, type Item = B;
sourcefn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>ⓘNotable traits for FlatMap<I, U, F>impl<I: Iterator, U: IntoIterator, F> Iterator for FlatMap<I, U, F> where
F: FnMut(I::Item) -> U, type Item = U::Item;
where
Self: Sized,
U: IntoIterator,
F: FnMut(Self::Item) -> U,
fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>ⓘNotable traits for FlatMap<I, U, F>impl<I: Iterator, U: IntoIterator, F> Iterator for FlatMap<I, U, F> where
F: FnMut(I::Item) -> U, type Item = U::Item;
where
Self: Sized,
U: IntoIterator,
F: FnMut(Self::Item) -> U,
F: FnMut(I::Item) -> U, type Item = U::Item;
Creates an iterator that works like map, but flattens nested structure. Read more
1.29.0 · sourcefn flatten(self) -> Flatten<Self>ⓘNotable traits for Flatten<I>impl<I, U> Iterator for Flatten<I> where
I: Iterator<Item: IntoIterator<IntoIter = U, Item = U::Item>>,
U: Iterator, type Item = U::Item;
where
Self: Sized,
Self::Item: IntoIterator,
fn flatten(self) -> Flatten<Self>ⓘNotable traits for Flatten<I>impl<I, U> Iterator for Flatten<I> where
I: Iterator<Item: IntoIterator<IntoIter = U, Item = U::Item>>,
U: Iterator, type Item = U::Item;
where
Self: Sized,
Self::Item: IntoIterator,
I: Iterator<Item: IntoIterator<IntoIter = U, Item = U::Item>>,
U: Iterator, type Item = U::Item;
Creates an iterator that flattens nested structure. Read more
sourcefn fuse(self) -> Fuse<Self>ⓘNotable traits for Fuse<I>impl<I> Iterator for Fuse<I> where
I: Iterator, type Item = <I as Iterator>::Item;
where
Self: Sized,
fn fuse(self) -> Fuse<Self>ⓘNotable traits for Fuse<I>impl<I> Iterator for Fuse<I> where
I: Iterator, type Item = <I as Iterator>::Item;
where
Self: Sized,
I: Iterator, type Item = <I as Iterator>::Item;
sourcefn inspect<F>(self, f: F) -> Inspect<Self, F>ⓘNotable traits for Inspect<I, F>impl<I: Iterator, F> Iterator for Inspect<I, F> where
F: FnMut(&I::Item), type Item = I::Item;
where
Self: Sized,
F: FnMut(&Self::Item),
fn inspect<F>(self, f: F) -> Inspect<Self, F>ⓘNotable traits for Inspect<I, F>impl<I: Iterator, F> Iterator for Inspect<I, F> where
F: FnMut(&I::Item), type Item = I::Item;
where
Self: Sized,
F: FnMut(&Self::Item),
F: FnMut(&I::Item), type Item = I::Item;
Does something with each element of an iterator, passing the value on. Read more
sourcefn by_ref(&mut self) -> &mut Self where
Self: Sized,
fn by_ref(&mut self) -> &mut Self where
Self: Sized,
Borrows an iterator, rather than consuming it. Read more
sourcefn collect<B: FromIterator<Self::Item>>(self) -> B where
Self: Sized,
fn collect<B: FromIterator<Self::Item>>(self) -> B where
Self: Sized,
Transforms an iterator into a collection. Read more
sourcefn try_collect<B>(
&mut self
) -> <<Self::Item as Try>::Residual as Residual<B>>::TryType where
Self: Sized,
<Self as Iterator>::Item: Try,
<<Self as Iterator>::Item as Try>::Residual: Residual<B>,
B: FromIterator<<Self::Item as Try>::Output>,
fn try_collect<B>(
&mut self
) -> <<Self::Item as Try>::Residual as Residual<B>>::TryType where
Self: Sized,
<Self as Iterator>::Item: Try,
<<Self as Iterator>::Item as Try>::Residual: Residual<B>,
B: FromIterator<<Self::Item as Try>::Output>,
Fallibly transforms an iterator into a collection, short circuiting if a failure is encountered. Read more
sourcefn collect_into<E: Extend<Self::Item>>(self, collection: &mut E) -> &mut E where
Self: Sized,
fn collect_into<E: Extend<Self::Item>>(self, collection: &mut E) -> &mut E where
Self: Sized,
Collects all the items from an iterator into a collection. Read more
sourcefn partition<B, F>(self, f: F) -> (B, B) where
Self: Sized,
B: Default + Extend<Self::Item>,
F: FnMut(&Self::Item) -> bool,
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
sourcefn partition_in_place<'a, T: 'a, P>(self, predicate: P) -> usize where
Self: Sized + DoubleEndedIterator<Item = &'a mut T>,
P: FnMut(&T) -> bool,
fn partition_in_place<'a, T: 'a, P>(self, predicate: P) -> usize where
Self: Sized + DoubleEndedIterator<Item = &'a mut T>,
P: FnMut(&T) -> bool,
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
sourcefn is_partitioned<P>(self, predicate: P) -> bool where
Self: Sized,
P: FnMut(Self::Item) -> bool,
fn is_partitioned<P>(self, predicate: P) -> bool where
Self: Sized,
P: FnMut(Self::Item) -> bool,
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 · sourcefn try_for_each<F, R>(&mut self, f: F) -> R where
Self: Sized,
F: FnMut(Self::Item) -> R,
R: Try<Output = ()>,
fn try_for_each<F, R>(&mut self, f: F) -> R where
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
1.51.0 · sourcefn reduce<F>(self, f: F) -> Option<Self::Item> where
Self: Sized,
F: FnMut(Self::Item, Self::Item) -> Self::Item,
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
sourcefn try_reduce<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<R::Output>>>::TryType where
Self: Sized,
F: FnMut(Self::Item, Self::Item) -> R,
R: Try<Output = Self::Item>,
R::Residual: Residual<Option<Self::Item>>,
fn try_reduce<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<R::Output>>>::TryType where
Self: Sized,
F: FnMut(Self::Item, Self::Item) -> R,
R: Try<Output = Self::Item>,
R::Residual: Residual<Option<Self::Item>>,
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
sourcefn all<F>(&mut self, f: F) -> bool where
Self: Sized,
F: FnMut(Self::Item) -> bool,
fn all<F>(&mut self, f: F) -> bool where
Self: Sized,
F: FnMut(Self::Item) -> bool,
Tests if every element of the iterator matches a predicate. Read more
sourcefn any<F>(&mut self, f: F) -> bool where
Self: Sized,
F: FnMut(Self::Item) -> bool,
fn any<F>(&mut self, f: F) -> bool where
Self: Sized,
F: FnMut(Self::Item) -> bool,
Tests if any element of the iterator matches a predicate. Read more
sourcefn find<P>(&mut self, predicate: P) -> Option<Self::Item> where
Self: Sized,
P: FnMut(&Self::Item) -> bool,
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 · sourcefn find_map<B, F>(&mut self, f: F) -> Option<B> where
Self: Sized,
F: FnMut(Self::Item) -> Option<B>,
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
sourcefn try_find<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryType where
Self: Sized,
F: FnMut(&Self::Item) -> R,
R: Try<Output = bool>,
R::Residual: Residual<Option<Self::Item>>,
fn try_find<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryType where
Self: Sized,
F: FnMut(&Self::Item) -> R,
R: Try<Output = bool>,
R::Residual: Residual<Option<Self::Item>>,
Applies function to the elements of iterator and returns the first true result or the first error. Read more
sourcefn position<P>(&mut self, predicate: P) -> Option<usize> where
Self: Sized,
P: FnMut(Self::Item) -> bool,
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
sourcefn rposition<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(Self::Item) -> bool,
Self: Sized + ExactSizeIterator + DoubleEndedIterator,
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
sourcefn max(self) -> Option<Self::Item> where
Self: Sized,
Self::Item: Ord,
fn max(self) -> Option<Self::Item> where
Self: Sized,
Self::Item: Ord,
Returns the maximum element of an iterator. Read more
sourcefn min(self) -> Option<Self::Item> where
Self: Sized,
Self::Item: Ord,
fn min(self) -> Option<Self::Item> where
Self: Sized,
Self::Item: Ord,
Returns the minimum element of an iterator. Read more
1.6.0 · sourcefn max_by_key<B: Ord, F>(self, f: F) -> Option<Self::Item> where
Self: Sized,
F: FnMut(&Self::Item) -> B,
fn max_by_key<B: Ord, F>(self, f: F) -> Option<Self::Item> where
Self: Sized,
F: FnMut(&Self::Item) -> B,
Returns the element that gives the maximum value from the specified function. Read more
1.15.0 · sourcefn max_by<F>(self, compare: F) -> Option<Self::Item> where
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
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
1.6.0 · sourcefn min_by_key<B: Ord, F>(self, f: F) -> Option<Self::Item> where
Self: Sized,
F: FnMut(&Self::Item) -> B,
fn min_by_key<B: Ord, F>(self, f: F) -> Option<Self::Item> where
Self: Sized,
F: FnMut(&Self::Item) -> B,
Returns the element that gives the minimum value from the specified function. Read more
1.15.0 · sourcefn min_by<F>(self, compare: F) -> Option<Self::Item> where
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
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
sourcefn rev(self) -> Rev<Self>ⓘNotable traits for Rev<I>impl<I> Iterator for Rev<I> where
I: DoubleEndedIterator, type Item = <I as Iterator>::Item;
where
Self: Sized + DoubleEndedIterator,
fn rev(self) -> Rev<Self>ⓘNotable traits for Rev<I>impl<I> Iterator for Rev<I> where
I: DoubleEndedIterator, type Item = <I as Iterator>::Item;
where
Self: Sized + DoubleEndedIterator,
I: DoubleEndedIterator, type Item = <I as Iterator>::Item;
Reverses an iterator’s direction. Read more
sourcefn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB) where
FromA: Default + Extend<A>,
FromB: Default + Extend<B>,
Self: Sized + Iterator<Item = (A, B)>,
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 · sourcefn copied<'a, T: 'a>(self) -> Copied<Self>ⓘNotable traits for Copied<I>impl<'a, I, T: 'a> Iterator for Copied<I> where
I: Iterator<Item = &'a T>,
T: Copy, type Item = T;
where
Self: Sized + Iterator<Item = &'a T>,
T: Copy,
fn copied<'a, T: 'a>(self) -> Copied<Self>ⓘNotable traits for Copied<I>impl<'a, I, T: 'a> Iterator for Copied<I> where
I: Iterator<Item = &'a T>,
T: Copy, type Item = T;
where
Self: Sized + Iterator<Item = &'a T>,
T: Copy,
I: Iterator<Item = &'a T>,
T: Copy, type Item = T;
Creates an iterator which copies all of its elements. Read more
sourcefn cloned<'a, T: 'a>(self) -> Cloned<Self>ⓘNotable traits for Cloned<I>impl<'a, I, T: 'a> Iterator for Cloned<I> where
I: Iterator<Item = &'a T>,
T: Clone, type Item = T;
where
Self: Sized + Iterator<Item = &'a T>,
T: Clone,
fn cloned<'a, T: 'a>(self) -> Cloned<Self>ⓘNotable traits for Cloned<I>impl<'a, I, T: 'a> Iterator for Cloned<I> where
I: Iterator<Item = &'a T>,
T: Clone, type Item = T;
where
Self: Sized + Iterator<Item = &'a T>,
T: Clone,
I: Iterator<Item = &'a T>,
T: Clone, type Item = T;
sourcefn cycle(self) -> Cycle<Self>ⓘNotable traits for Cycle<I>impl<I> Iterator for Cycle<I> where
I: Clone + Iterator, type Item = <I as Iterator>::Item;
where
Self: Sized + Clone,
fn cycle(self) -> Cycle<Self>ⓘNotable traits for Cycle<I>impl<I> Iterator for Cycle<I> where
I: Clone + Iterator, type Item = <I as Iterator>::Item;
where
Self: Sized + Clone,
I: Clone + Iterator, type Item = <I as Iterator>::Item;
Repeats an iterator endlessly. Read more
1.11.0 · sourcefn sum<S>(self) -> S where
Self: Sized,
S: Sum<Self::Item>,
fn sum<S>(self) -> S where
Self: Sized,
S: Sum<Self::Item>,
Sums the elements of an iterator. Read more
1.11.0 · sourcefn product<P>(self) -> P where
Self: Sized,
P: Product<Self::Item>,
fn product<P>(self) -> P where
Self: Sized,
P: Product<Self::Item>,
Iterates over the entire iterator, multiplying all the elements Read more
1.5.0 · sourcefn cmp<I>(self, other: I) -> Ordering where
I: IntoIterator<Item = Self::Item>,
Self::Item: Ord,
Self: Sized,
fn cmp<I>(self, other: I) -> Ordering where
I: IntoIterator<Item = Self::Item>,
Self::Item: Ord,
Self: Sized,
Lexicographically compares the elements of this Iterator
with those
of another. Read more
sourcefn cmp_by<I, F>(self, other: I, cmp: F) -> Ordering where
Self: Sized,
I: IntoIterator,
F: FnMut(Self::Item, I::Item) -> Ordering,
fn cmp_by<I, F>(self, other: I, cmp: F) -> Ordering where
Self: Sized,
I: IntoIterator,
F: FnMut(Self::Item, I::Item) -> Ordering,
Lexicographically compares the elements of this Iterator
with those
of another with respect to the specified comparison function. Read more
1.5.0 · sourcefn partial_cmp<I>(self, other: I) -> Option<Ordering> where
I: IntoIterator,
Self::Item: PartialOrd<I::Item>,
Self: Sized,
fn partial_cmp<I>(self, other: I) -> Option<Ordering> where
I: IntoIterator,
Self::Item: PartialOrd<I::Item>,
Self: Sized,
Lexicographically compares the elements of this Iterator
with those
of another. Read more
sourcefn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering> where
Self: Sized,
I: IntoIterator,
F: FnMut(Self::Item, I::Item) -> Option<Ordering>,
fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering> where
Self: Sized,
I: IntoIterator,
F: FnMut(Self::Item, I::Item) -> Option<Ordering>,
Lexicographically compares the elements of this Iterator
with those
of another with respect to the specified comparison function. Read more
1.5.0 · sourcefn eq<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialEq<I::Item>,
Self: Sized,
fn eq<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialEq<I::Item>,
Self: Sized,
sourcefn eq_by<I, F>(self, other: I, eq: F) -> bool where
Self: Sized,
I: IntoIterator,
F: FnMut(Self::Item, I::Item) -> bool,
fn eq_by<I, F>(self, other: I, eq: F) -> bool where
Self: Sized,
I: IntoIterator,
F: FnMut(Self::Item, I::Item) -> bool,
1.5.0 · sourcefn ne<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialEq<I::Item>,
Self: Sized,
fn ne<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialEq<I::Item>,
Self: Sized,
1.5.0 · sourcefn lt<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<I::Item>,
Self: Sized,
fn lt<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<I::Item>,
Self: Sized,
Determines if the elements of this Iterator
are lexicographically
less than those of another. Read more
1.5.0 · sourcefn le<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<I::Item>,
Self: Sized,
fn le<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<I::Item>,
Self: Sized,
Determines if the elements of this Iterator
are lexicographically
less or equal to those of another. Read more
1.5.0 · sourcefn gt<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<I::Item>,
Self: Sized,
fn gt<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<I::Item>,
Self: Sized,
Determines if the elements of this Iterator
are lexicographically
greater than those of another. Read more
1.5.0 · sourcefn ge<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<I::Item>,
Self: Sized,
fn ge<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<I::Item>,
Self: Sized,
Determines if the elements of this Iterator
are lexicographically
greater than or equal to those of another. Read more
sourcefn is_sorted(self) -> bool where
Self: Sized,
Self::Item: PartialOrd,
fn is_sorted(self) -> bool where
Self: Sized,
Self::Item: PartialOrd,
Checks if the elements of this iterator are sorted. Read more
sourcefn is_sorted_by<F>(self, compare: F) -> bool where
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,
fn is_sorted_by<F>(self, compare: F) -> bool where
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,
Checks if the elements of this iterator are sorted using the given comparator function. Read more
sourcefn is_sorted_by_key<F, K>(self, f: F) -> bool where
Self: Sized,
F: FnMut(Self::Item) -> K,
K: PartialOrd,
fn is_sorted_by_key<F, K>(self, f: F) -> bool where
Self: Sized,
F: FnMut(Self::Item) -> K,
K: PartialOrd,
Checks if the elements of this iterator are sorted using the given key extraction function. Read more
impl<I: FusedIterator> FusedIterator for Peekable<I>
impl<I> TrustedLen for Peekable<I> where
I: TrustedLen,
Auto Trait Implementations
impl<I> RefUnwindSafe for Peekable<I> where
I: RefUnwindSafe,
<I as Iterator>::Item: RefUnwindSafe,
impl<I> Send for Peekable<I> where
I: Send,
<I as Iterator>::Item: Send,
impl<I> Sync for Peekable<I> where
I: Sync,
<I as Iterator>::Item: Sync,
impl<I> Unpin for Peekable<I> where
I: Unpin,
<I as Iterator>::Item: Unpin,
impl<I> UnwindSafe for Peekable<I> where
I: UnwindSafe,
<I as Iterator>::Item: UnwindSafe,
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more