1.0.0[−][src]Trait std::iter::Iterator
An interface for dealing with iterators.
This is the main iterator trait. For more about the concept of iterators
generally, please see the module-level documentation. In particular, you
may want to know how to implement Iterator
.
Associated Types
type Item
The type of the elements being iterated over.
Required methods
fn next(&mut self) -> Option<Self::Item>
Advances the iterator and returns the next value.
Returns None
when iteration is finished. Individual iterator
implementations may choose to resume iteration, and so calling next()
again may or may not eventually start returning Some(Item)
again at some
point.
Examples
Basic usage:
let a = [1, 2, 3]; let mut iter = a.iter(); // A call to next() returns the next value... assert_eq!(Some(&1), iter.next()); assert_eq!(Some(&2), iter.next()); assert_eq!(Some(&3), iter.next()); // ... and then None once it's over. assert_eq!(None, iter.next()); // More calls may or may not return `None`. Here, they always will. assert_eq!(None, iter.next()); assert_eq!(None, iter.next());Run
Provided methods
fn size_hint(&self) -> (usize, Option<usize>)
Returns the bounds on the remaining length of the iterator.
Specifically, size_hint()
returns a tuple where the first element
is the lower bound, and the second element is the upper bound.
The second half of the tuple that is returned is an Option
<
usize
>
.
A None
here means that either there is no known upper bound, or the
upper bound is larger than usize
.
Implementation notes
It is not enforced that an iterator implementation yields the declared number of elements. A buggy iterator may yield less than the lower bound or more than the upper bound of elements.
size_hint()
is primarily intended to be used for optimizations such as
reserving space for the elements of the iterator, but must not be
trusted to e.g., omit bounds checks in unsafe code. An incorrect
implementation of size_hint()
should not lead to memory safety
violations.
That said, the implementation should provide a correct estimation, because otherwise it would be a violation of the trait's protocol.
The default implementation returns (0,
None
)
which is correct for any
iterator.
Examples
Basic usage:
let a = [1, 2, 3]; let iter = a.iter(); assert_eq!((3, Some(3)), iter.size_hint());Run
A more complex example:
// The even numbers from zero to ten. let iter = (0..10).filter(|x| x % 2 == 0); // We might iterate from zero to ten times. Knowing that it's five // exactly wouldn't be possible without executing filter(). assert_eq!((0, Some(10)), iter.size_hint()); // Let's add five more numbers with chain() let iter = (0..10).filter(|x| x % 2 == 0).chain(15..20); // now both bounds are increased by five assert_eq!((5, Some(15)), iter.size_hint());Run
Returning None
for an upper bound:
// an infinite iterator has no upper bound // and the maximum possible lower bound let iter = 0..; assert_eq!((usize::max_value(), None), iter.size_hint());Run
fn count(self) -> usize
Consumes the iterator, counting the number of iterations and returning it.
This method will evaluate the iterator until its next
returns
None
. Once None
is encountered, count()
returns the number of
times it called next
.
Overflow Behavior
The method does no guarding against overflows, so counting elements of
an iterator with more than usize::MAX
elements either produces the
wrong result or panics. If debug assertions are enabled, a panic is
guaranteed.
Panics
This function might panic if the iterator has more than usize::MAX
elements.
Examples
Basic usage:
let a = [1, 2, 3]; assert_eq!(a.iter().count(), 3); let a = [1, 2, 3, 4, 5]; assert_eq!(a.iter().count(), 5);Run
fn last(self) -> Option<Self::Item>
Consumes the iterator, returning the last element.
This method will evaluate the iterator until it returns None
. While
doing so, it keeps track of the current element. After None
is
returned, last()
will then return the last element it saw.
Examples
Basic usage:
let a = [1, 2, 3]; assert_eq!(a.iter().last(), Some(&3)); let a = [1, 2, 3, 4, 5]; assert_eq!(a.iter().last(), Some(&5));Run
fn nth(&mut self, n: usize) -> Option<Self::Item>
Returns the n
th element of the iterator.
Like most indexing operations, the count starts from zero, so nth(0)
returns the first value, nth(1)
the second, and so on.
Note that all preceding elements, as well as the returned element, will be
consumed from the iterator. That means that the preceding elements will be
discarded, and also that calling nth(0)
multiple times on the same iterator
will return different elements.
nth()
will return None
if n
is greater than or equal to the length of the
iterator.
Examples
Basic usage:
let a = [1, 2, 3]; assert_eq!(a.iter().nth(1), Some(&2));Run
Calling nth()
multiple times doesn't rewind the iterator:
let a = [1, 2, 3]; let mut iter = a.iter(); assert_eq!(iter.nth(1), Some(&2)); assert_eq!(iter.nth(1), None);Run
Returning None
if there are less than n + 1
elements:
let a = [1, 2, 3]; assert_eq!(a.iter().nth(10), None);Run
ⓘImportant traits for StepBy<I>fn step_by(self, step: usize) -> StepBy<Self>
1.28.0
Creates an iterator starting at the same point, but stepping by the given amount at each iteration.
Note 1: The first element of the iterator will always be returned, regardless of the step given.
Note 2: The time at which ignored elements are pulled is not fixed.
StepBy
behaves like the sequence next(), nth(step-1), nth(step-1), …
,
but is also free to behave like the sequence
advance_n_and_return_first(step), advance_n_and_return_first(step), …
Which way is used may change for some iterators for performance reasons.
The second way will advance the iterator earlier and may consume more items.
advance_n_and_return_first
is the equivalent of:
fn advance_n_and_return_first<I>(iter: &mut I, total_step: usize) -> Option<I::Item> where I: Iterator, { let next = iter.next(); if total_step > 1 { iter.nth(total_step-2); } next }Run
Panics
The method will panic if the given step is 0
.
Examples
Basic usage:
let a = [0, 1, 2, 3, 4, 5]; let mut iter = a.iter().step_by(2); assert_eq!(iter.next(), Some(&0)); assert_eq!(iter.next(), Some(&2)); assert_eq!(iter.next(), Some(&4)); assert_eq!(iter.next(), None);Run
ⓘImportant traits for Chain<A, B>fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter> where
U: IntoIterator<Item = Self::Item>,
U: IntoIterator<Item = Self::Item>,
Takes two iterators and creates a new iterator over both in sequence.
chain()
will return a new iterator which will first iterate over
values from the first iterator and then over values from the second
iterator.
In other words, it links two iterators together, in a chain. 🔗
Examples
Basic usage:
let a1 = [1, 2, 3]; let a2 = [4, 5, 6]; let mut iter = a1.iter().chain(a2.iter()); assert_eq!(iter.next(), Some(&1)); assert_eq!(iter.next(), Some(&2)); assert_eq!(iter.next(), Some(&3)); assert_eq!(iter.next(), Some(&4)); assert_eq!(iter.next(), Some(&5)); assert_eq!(iter.next(), Some(&6)); assert_eq!(iter.next(), None);Run
Since the argument to chain()
uses IntoIterator
, we can pass
anything that can be converted into an Iterator
, not just an
Iterator
itself. For example, slices (&[T]
) implement
IntoIterator
, and so can be passed to chain()
directly:
let s1 = &[1, 2, 3]; let s2 = &[4, 5, 6]; let mut iter = s1.iter().chain(s2); assert_eq!(iter.next(), Some(&1)); assert_eq!(iter.next(), Some(&2)); assert_eq!(iter.next(), Some(&3)); assert_eq!(iter.next(), Some(&4)); assert_eq!(iter.next(), Some(&5)); assert_eq!(iter.next(), Some(&6)); assert_eq!(iter.next(), None);Run
ⓘImportant traits for Zip<A, B>fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter> where
U: IntoIterator,
U: IntoIterator,
'Zips up' two iterators into a single iterator of pairs.
zip()
returns a new iterator that will iterate over two other
iterators, returning a tuple where the first element comes from the
first iterator, and the second element comes from the second iterator.
In other words, it zips two iterators together, into a single one.
If either iterator returns None
, next
from the zipped iterator
will return None
. If the first iterator returns None
, zip
will
short-circuit and next
will not be called on the second iterator.
Examples
Basic usage:
let a1 = [1, 2, 3]; let a2 = [4, 5, 6]; let mut iter = a1.iter().zip(a2.iter()); assert_eq!(iter.next(), Some((&1, &4))); assert_eq!(iter.next(), Some((&2, &5))); assert_eq!(iter.next(), Some((&3, &6))); assert_eq!(iter.next(), None);Run
Since the argument to zip()
uses IntoIterator
, we can pass
anything that can be converted into an Iterator
, not just an
Iterator
itself. For example, slices (&[T]
) implement
IntoIterator
, and so can be passed to zip()
directly:
let s1 = &[1, 2, 3]; let s2 = &[4, 5, 6]; let mut iter = s1.iter().zip(s2); assert_eq!(iter.next(), Some((&1, &4))); assert_eq!(iter.next(), Some((&2, &5))); assert_eq!(iter.next(), Some((&3, &6))); assert_eq!(iter.next(), None);Run
zip()
is often used to zip an infinite iterator to a finite one.
This works because the finite iterator will eventually return None
,
ending the zipper. Zipping with (0..)
can look a lot like enumerate
:
let enumerate: Vec<_> = "foo".chars().enumerate().collect(); let zipper: Vec<_> = (0..).zip("foo".chars()).collect(); assert_eq!((0, 'f'), enumerate[0]); assert_eq!((0, 'f'), zipper[0]); assert_eq!((1, 'o'), enumerate[1]); assert_eq!((1, 'o'), zipper[1]); assert_eq!((2, 'o'), enumerate[2]); assert_eq!((2, 'o'), zipper[2]);Run
ⓘImportant traits for Map<I, F>fn map<B, F>(self, f: F) -> Map<Self, F> where
F: FnMut(Self::Item) -> B,
F: FnMut(Self::Item) -> B,
Takes a closure and creates an iterator which calls that closure on each element.
map()
transforms one iterator into another, by means of its argument:
something that implements FnMut
. It produces a new iterator which
calls this closure on each element of the original iterator.
If you are good at thinking in types, you can think of map()
like this:
If you have an iterator that gives you elements of some type A
, and
you want an iterator of some other type B
, you can use map()
,
passing a closure that takes an A
and returns a B
.
map()
is conceptually similar to a for
loop. However, as map()
is
lazy, it is best used when you're already working with other iterators.
If you're doing some sort of looping for a side effect, it's considered
more idiomatic to use for
than map()
.
Examples
Basic usage:
let a = [1, 2, 3]; let mut iter = a.iter().map(|x| 2 * x); assert_eq!(iter.next(), Some(2)); assert_eq!(iter.next(), Some(4)); assert_eq!(iter.next(), Some(6)); assert_eq!(iter.next(), None);Run
If you're doing some sort of side effect, prefer for
to map()
:
// don't do this: (0..5).map(|x| println!("{}", x)); // it won't even execute, as it is lazy. Rust will warn you about this. // Instead, use for: for x in 0..5 { println!("{}", x); }Run
fn for_each<F>(self, f: F) where
F: FnMut(Self::Item),
1.21.0
F: FnMut(Self::Item),
Calls a closure on each element of an iterator.
This is equivalent to using a for
loop on the iterator, although
break
and continue
are not possible from a closure. It's generally
more idiomatic to use a for
loop, but for_each
may be more legible
when processing items at the end of longer iterator chains. In some
cases for_each
may also be faster than a loop, because it will use
internal iteration on adaptors like Chain
.
Examples
Basic usage:
use std::sync::mpsc::channel; let (tx, rx) = channel(); (0..5).map(|x| x * 2 + 1) .for_each(move |x| tx.send(x).unwrap()); let v: Vec<_> = rx.iter().collect(); assert_eq!(v, vec![1, 3, 5, 7, 9]);Run
For such a small example, a for
loop may be cleaner, but for_each
might be preferable to keep a functional style with longer iterators:
(0..5).flat_map(|x| x * 100 .. x * 110) .enumerate() .filter(|&(i, x)| (i + x) % 3 == 0) .for_each(|(i, x)| println!("{}:{}", i, x));Run
ⓘImportant traits for Filter<I, P>fn filter<P>(self, predicate: P) -> Filter<Self, P> where
P: FnMut(&Self::Item) -> bool,
P: FnMut(&Self::Item) -> bool,
Creates an iterator which uses a closure to determine if an element should be yielded.
The closure must return true
or false
. filter()
creates an
iterator which calls this closure on each element. If the closure
returns true
, then the element is returned. If the closure returns
false
, it will try again, and call the closure on the next element,
seeing if it passes the test.
Examples
Basic usage:
let a = [0i32, 1, 2]; let mut iter = a.iter().filter(|x| x.is_positive()); assert_eq!(iter.next(), Some(&1)); assert_eq!(iter.next(), Some(&2)); assert_eq!(iter.next(), None);Run
Because the closure passed to filter()
takes a reference, and many
iterators iterate over references, this leads to a possibly confusing
situation, where the type of the closure is a double reference:
let a = [0, 1, 2]; let mut iter = a.iter().filter(|x| **x > 1); // need two *s! assert_eq!(iter.next(), Some(&2)); assert_eq!(iter.next(), None);Run
It's common to instead use destructuring on the argument to strip away one:
let a = [0, 1, 2]; let mut iter = a.iter().filter(|&x| *x > 1); // both & and * assert_eq!(iter.next(), Some(&2)); assert_eq!(iter.next(), None);Run
or both:
let a = [0, 1, 2]; let mut iter = a.iter().filter(|&&x| x > 1); // two &s assert_eq!(iter.next(), Some(&2)); assert_eq!(iter.next(), None);Run
of these layers.
ⓘImportant traits for FilterMap<I, F>fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F> where
F: FnMut(Self::Item) -> Option<B>,
F: FnMut(Self::Item) -> Option<B>,
Creates an iterator that both filters and maps.
The closure must return an Option<T>
. filter_map
creates an
iterator which calls this closure on each element. If the closure
returns Some(element)
, then that element is returned. If the
closure returns None
, it will try again, and call the closure on the
next element, seeing if it will return Some
.
Why filter_map
and not just filter
and map
? The key is in this
part:
If the closure returns
Some(element)
, then that element is returned.
In other words, it removes the Option<T>
layer automatically. If your
mapping is already returning an Option<T>
and you want to skip over
None
s, then filter_map
is much, much nicer to use.
Examples
Basic usage:
let a = ["1", "lol", "3", "NaN", "5"]; let mut iter = a.iter().filter_map(|s| s.parse().ok()); assert_eq!(iter.next(), Some(1)); assert_eq!(iter.next(), Some(3)); assert_eq!(iter.next(), Some(5)); assert_eq!(iter.next(), None);Run
Here's the same example, but with filter
and map
:
let a = ["1", "lol", "3", "NaN", "5"]; let mut iter = a.iter().map(|s| s.parse()).filter(|s| s.is_ok()).map(|s| s.unwrap()); assert_eq!(iter.next(), Some(1)); assert_eq!(iter.next(), Some(3)); assert_eq!(iter.next(), Some(5)); assert_eq!(iter.next(), None);Run
ⓘImportant traits for Enumerate<I>fn enumerate(self) -> Enumerate<Self>
Creates an iterator which gives the current iteration count as well as the next value.
The iterator returned yields pairs (i, val)
, where i
is the
current index of iteration and val
is the value returned by the
iterator.
enumerate()
keeps its count as a usize
. If you want to count by a
different sized integer, the zip
function provides similar
functionality.
Overflow Behavior
The method does no guarding against overflows, so enumerating more than
usize::MAX
elements either produces the wrong result or panics. If
debug assertions are enabled, a panic is guaranteed.
Panics
The returned iterator might panic if the to-be-returned index would
overflow a usize
.
Examples
let a = ['a', 'b', 'c']; let mut iter = a.iter().enumerate(); assert_eq!(iter.next(), Some((0, &'a'))); assert_eq!(iter.next(), Some((1, &'b'))); assert_eq!(iter.next(), Some((2, &'c'))); assert_eq!(iter.next(), None);Run
ⓘImportant traits for Peekable<I>fn peekable(self) -> Peekable<Self>
Creates an iterator which can use peek
to look at the next element of
the iterator without consuming it.
Adds a peek
method to an iterator. See its documentation for
more information.
Note that the underlying iterator is still advanced when peek
is
called for the first time: In order to retrieve the next element,
next
is called on the underlying iterator, hence any side effects (i.e.
anything other than fetching the next value) of the next
method
will occur.
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)); // we can peek() multiple times, the iterator won't advance 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);Run
ⓘImportant traits for SkipWhile<I, P>fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P> where
P: FnMut(&Self::Item) -> bool,
P: FnMut(&Self::Item) -> bool,
Creates an iterator that skip
s elements based on a predicate.
skip_while()
takes a closure as an argument. It will call this
closure on each element of the iterator, and ignore elements
until it returns false
.
After false
is returned, skip_while()
's job is over, and the
rest of the elements are yielded.
Examples
Basic usage:
let a = [-1i32, 0, 1]; let mut iter = a.iter().skip_while(|x| x.is_negative()); assert_eq!(iter.next(), Some(&0)); assert_eq!(iter.next(), Some(&1)); assert_eq!(iter.next(), None);Run
Because the closure passed to skip_while()
takes a reference, and many
iterators iterate over references, this leads to a possibly confusing
situation, where the type of the closure is a double reference:
let a = [-1, 0, 1]; let mut iter = a.iter().skip_while(|x| **x < 0); // need two *s! assert_eq!(iter.next(), Some(&0)); assert_eq!(iter.next(), Some(&1)); assert_eq!(iter.next(), None);Run
Stopping after an initial false
:
let a = [-1, 0, 1, -2]; let mut iter = a.iter().skip_while(|x| **x < 0); assert_eq!(iter.next(), Some(&0)); assert_eq!(iter.next(), Some(&1)); // while this would have been false, since we already got a false, // skip_while() isn't used any more assert_eq!(iter.next(), Some(&-2)); assert_eq!(iter.next(), None);Run
ⓘImportant traits for TakeWhile<I, P>fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P> where
P: FnMut(&Self::Item) -> bool,
P: FnMut(&Self::Item) -> bool,
Creates an iterator that yields elements based on a predicate.
take_while()
takes a closure as an argument. It will call this
closure on each element of the iterator, and yield elements
while it returns true
.
After false
is returned, take_while()
's job is over, and the
rest of the elements are ignored.
Examples
Basic usage:
let a = [-1i32, 0, 1]; let mut iter = a.iter().take_while(|x| x.is_negative()); assert_eq!(iter.next(), Some(&-1)); assert_eq!(iter.next(), None);Run
Because the closure passed to take_while()
takes a reference, and many
iterators iterate over references, this leads to a possibly confusing
situation, where the type of the closure is a double reference:
let a = [-1, 0, 1]; let mut iter = a.iter().take_while(|x| **x < 0); // need two *s! assert_eq!(iter.next(), Some(&-1)); assert_eq!(iter.next(), None);Run
Stopping after an initial false
:
let a = [-1, 0, 1, -2]; let mut iter = a.iter().take_while(|x| **x < 0); assert_eq!(iter.next(), Some(&-1)); // We have more elements that are less than zero, but since we already // got a false, take_while() isn't used any more assert_eq!(iter.next(), None);Run
Because take_while()
needs to look at the value in order to see if it
should be included or not, consuming iterators will see that it is
removed:
let a = [1, 2, 3, 4]; let mut iter = a.iter(); let result: Vec<i32> = iter.by_ref() .take_while(|n| **n != 3) .cloned() .collect(); assert_eq!(result, &[1, 2]); let result: Vec<i32> = iter.cloned().collect(); assert_eq!(result, &[4]);Run
The 3
is no longer there, because it was consumed in order to see if
the iteration should stop, but wasn't placed back into the iterator.
ⓘImportant traits for Skip<I>fn skip(self, n: usize) -> Skip<Self>
Creates an iterator that skips the first n
elements.
After they have been consumed, the rest of the elements are yielded.
Rather than overriding this method directly, instead override the nth
method.
Examples
Basic usage:
let a = [1, 2, 3]; let mut iter = a.iter().skip(2); assert_eq!(iter.next(), Some(&3)); assert_eq!(iter.next(), None);Run
ⓘImportant traits for Take<I>fn take(self, n: usize) -> Take<Self>
Creates an iterator that yields its first n
elements.
Examples
Basic usage:
let a = [1, 2, 3]; let mut iter = a.iter().take(2); assert_eq!(iter.next(), Some(&1)); assert_eq!(iter.next(), Some(&2)); assert_eq!(iter.next(), None);Run
take()
is often used with an infinite iterator, to make it finite:
let mut iter = (0..).take(3); assert_eq!(iter.next(), Some(0)); assert_eq!(iter.next(), Some(1)); assert_eq!(iter.next(), Some(2)); assert_eq!(iter.next(), None);Run
ⓘ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>,
F: FnMut(&mut St, Self::Item) -> Option<B>,
An iterator adaptor similar to fold
that holds internal state and
produces a new iterator.
scan()
takes two arguments: an initial value which seeds the internal
state, and a closure with two arguments, the first being a mutable
reference to the internal state and the second an iterator element.
The closure can assign to the internal state to share state between
iterations.
On iteration, the closure will be applied to each element of the
iterator and the return value from the closure, an Option
, is
yielded by the iterator.
Examples
Basic usage:
let a = [1, 2, 3]; let mut iter = a.iter().scan(1, |state, &x| { // each iteration, we'll multiply the state by the element *state = *state * x; // then, we'll yield the negation of the state Some(-*state) }); assert_eq!(iter.next(), Some(-1)); assert_eq!(iter.next(), Some(-2)); assert_eq!(iter.next(), Some(-6)); assert_eq!(iter.next(), None);Run
ⓘ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,
F: FnMut(Self::Item) -> U,
U: IntoIterator,
Creates an iterator that works like map, but flattens nested structure.
The map
adapter is very useful, but only when the closure
argument produces values. If it produces an iterator instead, there's
an extra layer of indirection. flat_map()
will remove this extra layer
on its own.
You can think of flat_map(f)
as the semantic equivalent
of map
ping, and then flatten
ing as in map(f).flatten()
.
Another way of thinking about flat_map()
: map
's closure returns
one item for each element, and flat_map()
's closure returns an
iterator for each element.
Examples
Basic usage:
let words = ["alpha", "beta", "gamma"]; // chars() returns an iterator let merged: String = words.iter() .flat_map(|s| s.chars()) .collect(); assert_eq!(merged, "alphabetagamma");Run
ⓘImportant traits for Flatten<I>fn flatten(self) -> Flatten<Self> where
Self::Item: IntoIterator,
1.29.0
Self::Item: IntoIterator,
Creates an iterator that flattens nested structure.
This is useful when you have an iterator of iterators or an iterator of things that can be turned into iterators and you want to remove one level of indirection.
Examples
Basic usage:
let data = vec![vec![1, 2, 3, 4], vec![5, 6]]; let flattened = data.into_iter().flatten().collect::<Vec<u8>>(); assert_eq!(flattened, &[1, 2, 3, 4, 5, 6]);Run
Mapping and then flattening:
let words = ["alpha", "beta", "gamma"]; // chars() returns an iterator let merged: String = words.iter() .map(|s| s.chars()) .flatten() .collect(); assert_eq!(merged, "alphabetagamma");Run
You can also rewrite this in terms of flat_map()
, which is preferable
in this case since it conveys intent more clearly:
let words = ["alpha", "beta", "gamma"]; // chars() returns an iterator let merged: String = words.iter() .flat_map(|s| s.chars()) .collect(); assert_eq!(merged, "alphabetagamma");Run
Flattening once only removes one level of nesting:
let d3 = [[[1, 2], [3, 4]], [[5, 6], [7, 8]]]; let d2 = d3.iter().flatten().collect::<Vec<_>>(); assert_eq!(d2, [&[1, 2], &[3, 4], &[5, 6], &[7, 8]]); let d1 = d3.iter().flatten().flatten().collect::<Vec<_>>(); assert_eq!(d1, [&1, &2, &3, &4, &5, &6, &7, &8]);Run
Here we see that flatten()
does not perform a "deep" flatten.
Instead, only one level of nesting is removed. That is, if you
flatten()
a three-dimensional array the result will be
two-dimensional and not one-dimensional. To get a one-dimensional
structure, you have to flatten()
again.
ⓘImportant traits for Fuse<I>fn fuse(self) -> Fuse<Self>
Creates an iterator which ends after the first None
.
After an iterator returns None
, future calls may or may not yield
Some(T)
again. fuse()
adapts an iterator, ensuring that after a
None
is given, it will always return None
forever.
Examples
Basic usage:
// an iterator which alternates between Some and None struct Alternate { state: i32, } impl Iterator for Alternate { type Item = i32; fn next(&mut self) -> Option<i32> { let val = self.state; self.state = self.state + 1; // if it's even, Some(i32), else None if val % 2 == 0 { Some(val) } else { None } } } let mut iter = Alternate { state: 0 }; // we can see our iterator going back and forth assert_eq!(iter.next(), Some(0)); assert_eq!(iter.next(), None); assert_eq!(iter.next(), Some(2)); assert_eq!(iter.next(), None); // however, once we fuse it... let mut iter = iter.fuse(); assert_eq!(iter.next(), Some(4)); assert_eq!(iter.next(), None); // it will always return `None` after the first time. assert_eq!(iter.next(), None); assert_eq!(iter.next(), None); assert_eq!(iter.next(), None);Run
ⓘImportant traits for Inspect<I, F>fn inspect<F>(self, f: F) -> Inspect<Self, F> where
F: FnMut(&Self::Item),
F: FnMut(&Self::Item),
Do something with each element of an iterator, passing the value on.
When using iterators, you'll often chain several of them together.
While working on such code, you might want to check out what's
happening at various parts in the pipeline. To do that, insert
a call to inspect()
.
It's more common for inspect()
to be used as a debugging tool than to
exist in your final code, but applications may find it useful in certain
situations when errors need to be logged before being discarded.
Examples
Basic usage:
let a = [1, 4, 2, 3]; // this iterator sequence is complex. let sum = a.iter() .cloned() .filter(|x| x % 2 == 0) .fold(0, |sum, i| sum + i); println!("{}", sum); // let's add some inspect() calls to investigate what's happening let sum = a.iter() .cloned() .inspect(|x| println!("about to filter: {}", x)) .filter(|x| x % 2 == 0) .inspect(|x| println!("made it through filter: {}", x)) .fold(0, |sum, i| sum + i); println!("{}", sum);Run
This will print:
6
about to filter: 1
about to filter: 4
made it through filter: 4
about to filter: 2
made it through filter: 2
about to filter: 3
6
Logging errors before discarding them:
let lines = ["1", "2", "a"]; let sum: i32 = lines .iter() .map(|line| line.parse::<i32>()) .inspect(|num| { if let Err(ref e) = *num { println!("Parsing error: {}", e); } }) .filter_map(Result::ok) .sum(); println!("Sum: {}", sum);Run
This will print:
Parsing error: invalid digit found in string
Sum: 3
ⓘImportant traits for &'_ mut Ffn by_ref(&mut self) -> &mut Self
Borrows an iterator, rather than consuming it.
This is useful to allow applying iterator adaptors while still retaining ownership of the original iterator.
Examples
Basic usage:
let a = [1, 2, 3]; let iter = a.iter(); let sum: i32 = iter.take(5).fold(0, |acc, i| acc + i ); assert_eq!(sum, 6); // if we try to use iter again, it won't work. The following line // gives "error: use of moved value: `iter` // assert_eq!(iter.next(), None); // let's try that again let a = [1, 2, 3]; let mut iter = a.iter(); // instead, we add in a .by_ref() let sum: i32 = iter.by_ref().take(2).fold(0, |acc, i| acc + i ); assert_eq!(sum, 3); // now this is just fine: assert_eq!(iter.next(), Some(&3)); assert_eq!(iter.next(), None);Run
#[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>,
B: FromIterator<Self::Item>,
Transforms an iterator into a collection.
collect()
can take anything iterable, and turn it into a relevant
collection. This is one of the more powerful methods in the standard
library, used in a variety of contexts.
The most basic pattern in which collect()
is used is to turn one
collection into another. You take a collection, call iter
on it,
do a bunch of transformations, and then collect()
at the end.
One of the keys to collect()
's power is that many things you might
not think of as 'collections' actually are. For example, a String
is a collection of char
s. And a collection of
Result<T, E>
can be thought of as single
Result
<Collection<T>, E>
. See the examples below for more.
Because collect()
is so general, it can cause problems with type
inference. As such, collect()
is one of the few times you'll see
the syntax affectionately known as the 'turbofish': ::<>
. This
helps the inference algorithm understand specifically which collection
you're trying to collect into.
Examples
Basic usage:
let a = [1, 2, 3]; let doubled: Vec<i32> = a.iter() .map(|&x| x * 2) .collect(); assert_eq!(vec![2, 4, 6], doubled);Run
Note that we needed the : Vec<i32>
on the left-hand side. This is because
we could collect into, for example, a VecDeque<T>
instead:
use std::collections::VecDeque; let a = [1, 2, 3]; let doubled: VecDeque<i32> = a.iter().map(|&x| x * 2).collect(); assert_eq!(2, doubled[0]); assert_eq!(4, doubled[1]); assert_eq!(6, doubled[2]);Run
Using the 'turbofish' instead of annotating doubled
:
let a = [1, 2, 3]; let doubled = a.iter().map(|x| x * 2).collect::<Vec<i32>>(); assert_eq!(vec![2, 4, 6], doubled);Run
Because collect()
only cares about what you're collecting into, you can
still use a partial type hint, _
, with the turbofish:
let a = [1, 2, 3]; let doubled = a.iter().map(|x| x * 2).collect::<Vec<_>>(); assert_eq!(vec![2, 4, 6], doubled);Run
Using collect()
to make a String
:
let chars = ['g', 'd', 'k', 'k', 'n']; let hello: String = chars.iter() .map(|&x| x as u8) .map(|x| (x + 1) as char) .collect(); assert_eq!("hello", hello);Run
If you have a list of Result<T, E>
s, you can use collect()
to
see if any of them failed:
let results = [Ok(1), Err("nope"), Ok(3), Err("bad")]; let result: Result<Vec<_>, &str> = results.iter().cloned().collect(); // gives us the first error assert_eq!(Err("nope"), result); let results = [Ok(1), Ok(3)]; let result: Result<Vec<_>, &str> = results.iter().cloned().collect(); // gives us the list of answers assert_eq!(Ok(vec![1, 3]), result);Run
fn partition<B, F>(self, f: F) -> (B, B) where
B: Default + Extend<Self::Item>,
F: FnMut(&Self::Item) -> bool,
B: Default + Extend<Self::Item>,
F: FnMut(&Self::Item) -> bool,
Consumes an iterator, creating two collections from it.
The predicate passed to partition()
can return true
, or false
.
partition()
returns a pair, all of the elements for which it returned
true
, and all of the elements for which it returned false
.
Examples
Basic usage:
let a = [1, 2, 3]; let (even, odd): (Vec<i32>, Vec<i32>) = a .iter() .partition(|&n| n % 2 == 0); assert_eq!(even, vec![2]); assert_eq!(odd, vec![1, 3]);Run
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
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.
try_fold()
takes two arguments: an initial value, and a closure with
two arguments: an 'accumulator', and an element. The closure either
returns successfully, with the value that the accumulator should have
for the next iteration, or it returns failure, with an error value that
is propagated back to the caller immediately (short-circuiting).
The initial value is the value the accumulator will have on the first
call. If applying the closure succeeded against every element of the
iterator, try_fold()
returns the final accumulator as success.
Folding is useful whenever you have a collection of something, and want to produce a single value from it.
Note to Implementors
Most of the other (forward) methods have default implementations in
terms of this one, so try to implement this explicitly if it can
do something better than the default for
loop implementation.
In particular, try to have this call try_fold()
on the internal parts
from which this iterator is composed. If multiple calls are needed,
the ?
operator may be convenient for chaining the accumulator value
along, but beware any invariants that need to be upheld before those
early returns. This is a &mut self
method, so iteration needs to be
resumable after hitting an error here.
Examples
Basic usage:
let a = [1, 2, 3]; // the checked sum of all of the elements of the array let sum = a.iter().try_fold(0i8, |acc, &x| acc.checked_add(x)); assert_eq!(sum, Some(6));Run
Short-circuiting:
let a = [10, 20, 30, 100, 40, 50]; let mut it = a.iter(); // This sum overflows when adding the 100 element let sum = it.try_fold(0i8, |acc, &x| acc.checked_add(x)); assert_eq!(sum, None); // Because it short-circuited, the remaining elements are still // available through the iterator. assert_eq!(it.len(), 2); assert_eq!(it.next(), Some(&40));Run
fn try_for_each<F, R>(&mut self, f: F) -> R where
F: FnMut(Self::Item) -> R,
R: Try<Ok = ()>,
1.27.0
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.
This can also be thought of as the fallible form of for_each()
or as the stateless version of try_fold()
.
Examples
use std::fs::rename; use std::io::{stdout, Write}; use std::path::Path; let data = ["no_tea.txt", "stale_bread.json", "torrential_rain.png"]; let res = data.iter().try_for_each(|x| writeln!(stdout(), "{}", x)); assert!(res.is_ok()); let mut it = data.iter().cloned(); let res = it.try_for_each(|x| rename(x, Path::new(x).with_extension("old"))); assert!(res.is_err()); // It short-circuited, so the remaining items are still in the iterator: assert_eq!(it.next(), Some("stale_bread.json"));Run
fn fold<B, F>(self, init: B, f: F) -> B where
F: FnMut(B, Self::Item) -> B,
F: FnMut(B, Self::Item) -> B,
An iterator method that applies a function, producing a single, final value.
fold()
takes two arguments: an initial value, and a closure with two
arguments: an 'accumulator', and an element. The closure returns the value that
the accumulator should have for the next iteration.
The initial value is the value the accumulator will have on the first call.
After applying this closure to every element of the iterator, fold()
returns the accumulator.
This operation is sometimes called 'reduce' or 'inject'.
Folding is useful whenever you have a collection of something, and want to produce a single value from it.
Note: fold()
, and similar methods that traverse the entire iterator,
may not terminate for infinite iterators, even on traits for which a
result is determinable in finite time.
Examples
Basic usage:
let a = [1, 2, 3]; // the sum of all of the elements of the array let sum = a.iter().fold(0, |acc, x| acc + x); assert_eq!(sum, 6);Run
Let's walk through each step of the iteration here:
element | acc | x | result |
---|---|---|---|
0 | |||
1 | 0 | 1 | 1 |
2 | 1 | 2 | 3 |
3 | 3 | 3 | 6 |
And so, our final result, 6
.
It's common for people who haven't used iterators a lot to
use a for
loop with a list of things to build up a result. Those
can be turned into fold()
s:
let numbers = [1, 2, 3, 4, 5]; let mut result = 0; // for loop: for i in &numbers { result = result + i; } // fold: let result2 = numbers.iter().fold(0, |acc, &x| acc + x); // they're the same assert_eq!(result, result2);Run
fn all<F>(&mut self, f: F) -> bool where
F: FnMut(Self::Item) -> bool,
F: FnMut(Self::Item) -> bool,
Tests if every element of the iterator matches a predicate.
all()
takes a closure that returns true
or false
. It applies
this closure to each element of the iterator, and if they all return
true
, then so does all()
. If any of them return false
, it
returns false
.
all()
is short-circuiting; in other words, it will stop processing
as soon as it finds a false
, given that no matter what else happens,
the result will also be false
.
An empty iterator returns true
.
Examples
Basic usage:
let a = [1, 2, 3]; assert!(a.iter().all(|&x| x > 0)); assert!(!a.iter().all(|&x| x > 2));Run
Stopping at the first false
:
let a = [1, 2, 3]; let mut iter = a.iter(); assert!(!iter.all(|&x| x != 2)); // we can still use `iter`, as there are more elements. assert_eq!(iter.next(), Some(&3));Run
fn any<F>(&mut self, f: F) -> bool where
F: FnMut(Self::Item) -> bool,
F: FnMut(Self::Item) -> bool,
Tests if any element of the iterator matches a predicate.
any()
takes a closure that returns true
or false
. It applies
this closure to each element of the iterator, and if any of them return
true
, then so does any()
. If they all return false
, it
returns false
.
any()
is short-circuiting; in other words, it will stop processing
as soon as it finds a true
, given that no matter what else happens,
the result will also be true
.
An empty iterator returns false
.
Examples
Basic usage:
let a = [1, 2, 3]; assert!(a.iter().any(|&x| x > 0)); assert!(!a.iter().any(|&x| x > 5));Run
Stopping at the first true
:
let a = [1, 2, 3]; let mut iter = a.iter(); assert!(iter.any(|&x| x != 2)); // we can still use `iter`, as there are more elements. assert_eq!(iter.next(), Some(&2));Run
fn find<P>(&mut self, predicate: P) -> Option<Self::Item> where
P: FnMut(&Self::Item) -> bool,
P: FnMut(&Self::Item) -> bool,
Searches for an element of an iterator that satisfies a predicate.
find()
takes a closure that returns true
or false
. It applies
this closure to each element of the iterator, and if any of them return
true
, then find()
returns Some(element)
. If they all return
false
, it returns None
.
find()
is short-circuiting; in other words, it will stop processing
as soon as the closure returns true
.
Because find()
takes a reference, and many iterators iterate over
references, this leads to a possibly confusing situation where the
argument is a double reference. You can see this effect in the
examples below, with &&x
.
Examples
Basic usage:
let a = [1, 2, 3]; assert_eq!(a.iter().find(|&&x| x == 2), Some(&2)); assert_eq!(a.iter().find(|&&x| x == 5), None);Run
Stopping at the first true
:
let a = [1, 2, 3]; let mut iter = a.iter(); assert_eq!(iter.find(|&&x| x == 2), Some(&2)); // we can still use `iter`, as there are more elements. assert_eq!(iter.next(), Some(&3));Run
fn find_map<B, F>(&mut self, f: F) -> Option<B> where
F: FnMut(Self::Item) -> Option<B>,
1.30.0
F: FnMut(Self::Item) -> Option<B>,
Applies function to the elements of iterator and returns the first non-none result.
iter.find_map(f)
is equivalent to iter.filter_map(f).next()
.
Examples
let a = ["lol", "NaN", "2", "5"]; let first_number = a.iter().find_map(|s| s.parse().ok()); assert_eq!(first_number, Some(2));Run
fn position<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(Self::Item) -> bool,
P: FnMut(Self::Item) -> bool,
Searches for an element in an iterator, returning its index.
position()
takes a closure that returns true
or false
. It applies
this closure to each element of the iterator, and if one of them
returns true
, then position()
returns Some(index)
. If all of
them return false
, it returns None
.
position()
is short-circuiting; in other words, it will stop
processing as soon as it finds a true
.
Overflow Behavior
The method does no guarding against overflows, so if there are more
than usize::MAX
non-matching elements, it either produces the wrong
result or panics. If debug assertions are enabled, a panic is
guaranteed.
Panics
This function might panic if the iterator has more than usize::MAX
non-matching elements.
Examples
Basic usage:
let a = [1, 2, 3]; assert_eq!(a.iter().position(|&x| x == 2), Some(1)); assert_eq!(a.iter().position(|&x| x == 5), None);Run
Stopping at the first true
:
let a = [1, 2, 3, 4]; let mut iter = a.iter(); assert_eq!(iter.position(|&x| x >= 2), Some(1)); // we can still use `iter`, as there are more elements. assert_eq!(iter.next(), Some(&3)); // The returned index depends on iterator state assert_eq!(iter.position(|&x| x == 4), Some(0)); Run
fn rposition<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(Self::Item) -> bool,
Self: ExactSizeIterator + DoubleEndedIterator,
P: FnMut(Self::Item) -> bool,
Self: ExactSizeIterator + DoubleEndedIterator,
Searches for an element in an iterator from the right, returning its index.
rposition()
takes a closure that returns true
or false
. It applies
this closure to each element of the iterator, starting from the end,
and if one of them returns true
, then rposition()
returns
Some(index)
. If all of them return false
, it returns None
.
rposition()
is short-circuiting; in other words, it will stop
processing as soon as it finds a true
.
Examples
Basic usage:
let a = [1, 2, 3]; assert_eq!(a.iter().rposition(|&x| x == 3), Some(2)); assert_eq!(a.iter().rposition(|&x| x == 5), None);Run
Stopping at the first true
:
let a = [1, 2, 3]; let mut iter = a.iter(); assert_eq!(iter.rposition(|&x| x == 2), Some(1)); // we can still use `iter`, as there are more elements. assert_eq!(iter.next(), Some(&1));Run
fn max(self) -> Option<Self::Item> where
Self::Item: Ord,
Self::Item: Ord,
Returns the maximum element of an iterator.
If several elements are equally maximum, the last element is
returned. If the iterator is empty, None
is returned.
Examples
Basic usage:
let a = [1, 2, 3]; let b: Vec<u32> = Vec::new(); assert_eq!(a.iter().max(), Some(&3)); assert_eq!(b.iter().max(), None);Run
fn min(self) -> Option<Self::Item> where
Self::Item: Ord,
Self::Item: Ord,
Returns the minimum element of an iterator.
If several elements are equally minimum, the first element is
returned. If the iterator is empty, None
is returned.
Examples
Basic usage:
let a = [1, 2, 3]; let b: Vec<u32> = Vec::new(); assert_eq!(a.iter().min(), Some(&1)); assert_eq!(b.iter().min(), None);Run
fn max_by_key<B, F>(self, f: F) -> Option<Self::Item> where
B: Ord,
F: FnMut(&Self::Item) -> B,
1.6.0
B: Ord,
F: FnMut(&Self::Item) -> B,
Returns the element that gives the maximum value from the specified function.
If several elements are equally maximum, the last element is
returned. If the iterator is empty, None
is returned.
Examples
let a = [-3_i32, 0, 1, 5, -10]; assert_eq!(*a.iter().max_by_key(|x| x.abs()).unwrap(), -10);Run
fn max_by<F>(self, compare: F) -> Option<Self::Item> where
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
1.15.0
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
Returns the element that gives the maximum value with respect to the specified comparison function.
If several elements are equally maximum, the last element is
returned. If the iterator is empty, None
is returned.
Examples
let a = [-3_i32, 0, 1, 5, -10]; assert_eq!(*a.iter().max_by(|x, y| x.cmp(y)).unwrap(), 5);Run
fn min_by_key<B, F>(self, f: F) -> Option<Self::Item> where
B: Ord,
F: FnMut(&Self::Item) -> B,
1.6.0
B: Ord,
F: FnMut(&Self::Item) -> B,
Returns the element that gives the minimum value from the specified function.
If several elements are equally minimum, the first element is
returned. If the iterator is empty, None
is returned.
Examples
let a = [-3_i32, 0, 1, 5, -10]; assert_eq!(*a.iter().min_by_key(|x| x.abs()).unwrap(), 0);Run
fn min_by<F>(self, compare: F) -> Option<Self::Item> where
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
1.15.0
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
Returns the element that gives the minimum value with respect to the specified comparison function.
If several elements are equally minimum, the first element is
returned. If the iterator is empty, None
is returned.
Examples
let a = [-3_i32, 0, 1, 5, -10]; assert_eq!(*a.iter().min_by(|x, y| x.cmp(y)).unwrap(), -10);Run
ⓘImportant traits for Rev<I>fn rev(self) -> Rev<Self> where
Self: DoubleEndedIterator,
Self: DoubleEndedIterator,
Reverses an iterator's direction.
Usually, iterators iterate from left to right. After using rev()
,
an iterator will instead iterate from right to left.
This is only possible if the iterator has an end, so rev()
only
works on DoubleEndedIterator
s.
Examples
let a = [1, 2, 3]; let mut iter = a.iter().rev(); assert_eq!(iter.next(), Some(&3)); assert_eq!(iter.next(), Some(&2)); assert_eq!(iter.next(), Some(&1)); assert_eq!(iter.next(), None);Run
fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB) where
FromA: Default + Extend<A>,
FromB: Default + Extend<B>,
Self: Iterator<Item = (A, B)>,
FromA: Default + Extend<A>,
FromB: Default + Extend<B>,
Self: Iterator<Item = (A, B)>,
Converts an iterator of pairs into a pair of containers.
unzip()
consumes an entire iterator of pairs, producing two
collections: one from the left elements of the pairs, and one
from the right elements.
This function is, in some sense, the opposite of zip
.
Examples
Basic usage:
let a = [(1, 2), (3, 4)]; let (left, right): (Vec<_>, Vec<_>) = a.iter().cloned().unzip(); assert_eq!(left, [1, 3]); assert_eq!(right, [2, 4]);Run
ⓘImportant traits for Copied<I>fn copied<'a, T>(self) -> Copied<Self> where
Self: Iterator<Item = &'a T>,
T: 'a + Copy,
1.36.0
Self: Iterator<Item = &'a T>,
T: 'a + Copy,
Creates an iterator which copies all of its elements.
This is useful when you have an iterator over &T
, but you need an
iterator over T
.
Examples
Basic usage:
let a = [1, 2, 3]; let v_cloned: Vec<_> = a.iter().copied().collect(); // copied is the same as .map(|&x| x) let v_map: Vec<_> = a.iter().map(|&x| x).collect(); assert_eq!(v_cloned, vec![1, 2, 3]); assert_eq!(v_map, vec![1, 2, 3]);Run
ⓘImportant traits for Cloned<I>fn cloned<'a, T>(self) -> Cloned<Self> where
Self: Iterator<Item = &'a T>,
T: 'a + Clone,
Self: Iterator<Item = &'a T>,
T: 'a + Clone,
Creates an iterator which clone
s all of its elements.
This is useful when you have an iterator over &T
, but you need an
iterator over T
.
Examples
Basic usage:
let a = [1, 2, 3]; let v_cloned: Vec<_> = a.iter().cloned().collect(); // cloned is the same as .map(|&x| x), for integers let v_map: Vec<_> = a.iter().map(|&x| x).collect(); assert_eq!(v_cloned, vec![1, 2, 3]); assert_eq!(v_map, vec![1, 2, 3]);Run
ⓘImportant traits for Cycle<I>fn cycle(self) -> Cycle<Self> where
Self: Clone,
Self: Clone,
Repeats an iterator endlessly.
Instead of stopping at None
, the iterator will instead start again,
from the beginning. After iterating again, it will start at the
beginning again. And again. And again. Forever.
Examples
Basic usage:
let a = [1, 2, 3]; let mut it = a.iter().cycle(); assert_eq!(it.next(), Some(&1)); assert_eq!(it.next(), Some(&2)); assert_eq!(it.next(), Some(&3)); assert_eq!(it.next(), Some(&1)); assert_eq!(it.next(), Some(&2)); assert_eq!(it.next(), Some(&3)); assert_eq!(it.next(), Some(&1));Run
fn sum<S>(self) -> S where
S: Sum<Self::Item>,
1.11.0
S: Sum<Self::Item>,
Sums the elements of an iterator.
Takes each element, adds them together, and returns the result.
An empty iterator returns the zero value of the type.
Panics
When calling sum()
and a primitive integer type is being returned, this
method will panic if the computation overflows and debug assertions are
enabled.
Examples
Basic usage:
let a = [1, 2, 3]; let sum: i32 = a.iter().sum(); assert_eq!(sum, 6);Run
fn product<P>(self) -> P where
P: Product<Self::Item>,
1.11.0
P: Product<Self::Item>,
Iterates over the entire iterator, multiplying all the elements
An empty iterator returns the one value of the type.
Panics
When calling product()
and a primitive integer type is being returned,
method will panic if the computation overflows and debug assertions are
enabled.
Examples
fn factorial(n: u32) -> u32 { (1..=n).product() } assert_eq!(factorial(0), 1); assert_eq!(factorial(1), 1); assert_eq!(factorial(5), 120);Run
fn cmp<I>(self, other: I) -> Ordering where
I: IntoIterator<Item = Self::Item>,
Self::Item: Ord,
1.5.0
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>,
1.5.0
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>,
1.5.0
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>,
1.5.0
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>,
1.5.0
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>,
1.5.0
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>,
1.5.0
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>,
1.5.0
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.
fn is_sorted(self) -> bool where
Self::Item: PartialOrd<Self::Item>,
Self::Item: PartialOrd<Self::Item>,
🔬 This is a nightly-only experimental API. (is_sorted
#53485)
new API
Checks if the elements of this iterator are sorted.
That is, for each element a
and its following element b
, a <= b
must hold. If the
iterator yields exactly zero or one element, true
is returned.
Note that if Self::Item
is only PartialOrd
, but not Ord
, the above definition
implies that this function returns false
if any two consecutive items are not
comparable.
Examples
#![feature(is_sorted)] assert!([1, 2, 2, 9].iter().is_sorted()); assert!(![1, 3, 2, 4].iter().is_sorted()); assert!([0].iter().is_sorted()); assert!(std::iter::empty::<i32>().is_sorted()); assert!(![0.0, 1.0, std::f32::NAN].iter().is_sorted());Run
fn is_sorted_by<F>(self, compare: F) -> bool where
F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,
F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,
🔬 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.
Instead of using PartialOrd::partial_cmp
, this function uses the given compare
function to determine the ordering of two elements. Apart from that, it's equivalent to
is_sorted
; see its documentation for more information.
fn is_sorted_by_key<F, K>(self, f: F) -> bool where
F: FnMut(&Self::Item) -> K,
K: PartialOrd<K>,
F: FnMut(&Self::Item) -> K,
K: PartialOrd<K>,
🔬 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.
Instead of comparing the iterator's elements directly, this function compares the keys of
the elements, as determined by f
. Apart from that, it's equivalent to is_sorted
; see
its documentation for more information.
Examples
#![feature(is_sorted)] assert!(["c", "bb", "aaa"].iter().is_sorted_by_key(|s| s.len())); assert!(![-2i32, -1, 0, 3].iter().is_sorted_by_key(|n| n.abs()));Run
Implementations on Foreign Types
impl<'a> Iterator for Utf8LossyChunksIter<'a>
[src]
type Item = Utf8LossyChunk<'a>
fn next(&mut self) -> Option<Utf8LossyChunk<'a>>
[src]
impl<'a, K, V> Iterator for Iter<'a, K, V>
type Item = (&'a K, &'a V)
fn next(&mut self) -> Option<(&'a K, &'a V)>
fn size_hint(&self) -> (usize, Option<usize>)
impl<'a, K> Iterator for Iter<'a, K>
impl<K> Iterator for IntoIter<K>
impl<'a, T, S> Iterator for Union<'a, T, S> where
S: BuildHasher,
T: Eq + Hash,
S: BuildHasher,
T: Eq + Hash,
impl<'_, K> Iterator for Drain<'_, K>
impl<'a, K, V> Iterator for Keys<'a, K, V>
impl<'a, K, V> Iterator for ValuesMut<'a, K, V>
type Item = &'a mut V
fn next(&mut self) -> Option<&'a mut V>
fn size_hint(&self) -> (usize, Option<usize>)
impl<'a, K, V> Iterator for Drain<'a, K, V>
impl<K, V> Iterator for IntoIter<K, V>
impl<'a, K, V> Iterator for IterMut<'a, K, V>
type Item = (&'a K, &'a mut V)
fn next(&mut self) -> Option<(&'a K, &'a mut V)>
fn size_hint(&self) -> (usize, Option<usize>)
impl<'a, T, S> Iterator for SymmetricDifference<'a, T, S> where
S: BuildHasher,
T: Eq + Hash,
S: BuildHasher,
T: Eq + Hash,
impl<'a, K, V> Iterator for Values<'a, K, V>
impl<'a, T, S> Iterator for Intersection<'a, T, S> where
S: BuildHasher,
T: Eq + Hash,
S: BuildHasher,
T: Eq + Hash,
impl<'a, T, S> Iterator for Difference<'a, T, S> where
S: BuildHasher,
T: Eq + Hash,
Loading content...
S: BuildHasher,
T: Eq + Hash,
Implementors
impl Iterator for std::ascii::EscapeDefault
[src]
type Item = u8
fn next(&mut self) -> Option<u8>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl Iterator for std::char::EscapeDebug
[src]
type Item = char
fn next(&mut self) -> Option<char>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl Iterator for std::char::EscapeDefault
[src]
type Item = char
fn next(&mut self) -> Option<char>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn count(self) -> usize
[src]
fn nth(&mut self, n: usize) -> Option<char>
[src]
fn last(self) -> Option<char>
[src]
impl Iterator for std::char::EscapeUnicode
[src]
type Item = char
fn next(&mut self) -> Option<char>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn count(self) -> usize
[src]
fn last(self) -> Option<char>
[src]
impl Iterator for ToLowercase
[src]
type Item = char
fn next(&mut self) -> Option<char>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl Iterator for ToUppercase
[src]
type Item = char
fn next(&mut self) -> Option<char>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl Iterator for Args
[src]
type Item = String
fn next(&mut self) -> Option<String>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl Iterator for ArgsOs
[src]
type Item = OsString
fn next(&mut self) -> Option<OsString>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl Iterator for Vars
[src]
type Item = (String, String)
fn next(&mut self) -> Option<(String, String)>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl Iterator for VarsOs
[src]
type Item = (OsString, OsString)
fn next(&mut self) -> Option<(OsString, OsString)>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl Iterator for ReadDir
[src]
impl<'_> Iterator for std::str::Bytes<'_>
[src]
type Item = u8
fn next(&mut self) -> Option<u8>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn count(self) -> usize
[src]
fn last(self) -> Option<<Bytes<'_> as Iterator>::Item>
[src]
fn nth(&mut self, n: usize) -> Option<<Bytes<'_> as Iterator>::Item>
[src]
fn all<F>(&mut self, f: F) -> bool where
F: FnMut(<Bytes<'_> as Iterator>::Item) -> bool,
[src]
F: FnMut(<Bytes<'_> as Iterator>::Item) -> bool,
fn any<F>(&mut self, f: F) -> bool where
F: FnMut(<Bytes<'_> as Iterator>::Item) -> bool,
[src]
F: FnMut(<Bytes<'_> as Iterator>::Item) -> bool,
fn find<P>(&mut self, predicate: P) -> Option<<Bytes<'_> as Iterator>::Item> where
P: FnMut(&<Bytes<'_> as Iterator>::Item) -> bool,
[src]
P: FnMut(&<Bytes<'_> as Iterator>::Item) -> bool,
fn position<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(<Bytes<'_> as Iterator>::Item) -> bool,
[src]
P: FnMut(<Bytes<'_> as Iterator>::Item) -> bool,
fn rposition<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(<Bytes<'_> as Iterator>::Item) -> bool,
[src]
P: FnMut(<Bytes<'_> as Iterator>::Item) -> bool,
impl<'_> Iterator for std::string::Drain<'_>
[src]
type Item = char
fn next(&mut self) -> Option<char>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized,
[src]
I: Iterator + ?Sized,
type Item = <I as Iterator>::Item
fn next(&mut self) -> Option<<I as Iterator>::Item>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn nth(&mut self, n: usize) -> Option<<&'_ mut I as Iterator>::Item>
[src]
impl<'_, I> Iterator for Splice<'_, I> where
I: Iterator,
[src]
I: Iterator,
type Item = <I as Iterator>::Item
fn next(&mut self) -> Option<<Splice<'_, I> as Iterator>::Item>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'_, T> Iterator for std::collections::binary_heap::Drain<'_, T>
[src]
impl<'_, T> Iterator for std::collections::vec_deque::Drain<'_, T>
[src]
impl<'_, T> Iterator for std::vec::Drain<'_, T>
[src]
impl<'_, T, F> Iterator for std::collections::linked_list::DrainFilter<'_, T, F> where
F: FnMut(&mut T) -> bool,
[src]
F: FnMut(&mut T) -> bool,
impl<'_, T, F> Iterator for std::vec::DrainFilter<'_, T, F> where
F: FnMut(&mut T) -> bool,
[src]
F: FnMut(&mut T) -> bool,
impl<'a> Iterator for SplitPaths<'a>
[src]
type Item = PathBuf
fn next(&mut self) -> Option<PathBuf>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a> Iterator for ErrorIter<'a>
[src]
impl<'a> Iterator for std::net::Incoming<'a>
[src]
impl<'a> Iterator for std::os::unix::net::Incoming<'a>
[src]
type Item = Result<UnixStream>
fn next(&mut self) -> Option<Result<UnixStream>>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a> Iterator for EncodeWide<'a>
[src]
type Item = u16
fn next(&mut self) -> Option<u16>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a> Iterator for Ancestors<'a>
[src]
impl<'a> Iterator for Components<'a>
[src]
impl<'a> Iterator for std::path::Iter<'a>
[src]
impl<'a> Iterator for CharIndices<'a>
[src]
type Item = (usize, char)
fn next(&mut self) -> Option<(usize, char)>
[src]
fn count(self) -> usize
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn last(self) -> Option<(usize, char)>
[src]
impl<'a> Iterator for Chars<'a>
[src]
type Item = char
fn next(&mut self) -> Option<char>
[src]
fn count(self) -> usize
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn last(self) -> Option<char>
[src]
impl<'a> Iterator for EncodeUtf16<'a>
[src]
type Item = u16
fn next(&mut self) -> Option<u16>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a> Iterator for std::str::EscapeDebug<'a>
[src]
type Item = char
fn next(&mut self) -> Option<char>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <EscapeDebug<'a> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
EscapeDebug<'a>: Sized,
[src]
Fold: FnMut(Acc, <EscapeDebug<'a> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
EscapeDebug<'a>: Sized,
fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <EscapeDebug<'a> as Iterator>::Item) -> Acc,
[src]
Fold: FnMut(Acc, <EscapeDebug<'a> as Iterator>::Item) -> Acc,
impl<'a> Iterator for std::str::EscapeDefault<'a>
[src]
type Item = char
fn next(&mut self) -> Option<char>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <EscapeDefault<'a> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
EscapeDefault<'a>: Sized,
[src]
Fold: FnMut(Acc, <EscapeDefault<'a> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
EscapeDefault<'a>: Sized,
fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <EscapeDefault<'a> as Iterator>::Item) -> Acc,
[src]
Fold: FnMut(Acc, <EscapeDefault<'a> as Iterator>::Item) -> Acc,
impl<'a> Iterator for std::str::EscapeUnicode<'a>
[src]
type Item = char
fn next(&mut self) -> Option<char>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <EscapeUnicode<'a> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
EscapeUnicode<'a>: Sized,
[src]
Fold: FnMut(Acc, <EscapeUnicode<'a> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
EscapeUnicode<'a>: Sized,
fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <EscapeUnicode<'a> as Iterator>::Item) -> Acc,
[src]
Fold: FnMut(Acc, <EscapeUnicode<'a> as Iterator>::Item) -> Acc,
impl<'a> Iterator for std::str::Lines<'a>
[src]
type Item = &'a str
fn next(&mut self) -> Option<&'a str>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a> Iterator for LinesAny<'a>
[src]
type Item = &'a str
fn next(&mut self) -> Option<&'a str>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a> Iterator for SplitAsciiWhitespace<'a>
[src]
type Item = &'a str
fn next(&mut self) -> Option<&'a str>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a> Iterator for SplitWhitespace<'a>
[src]
type Item = &'a str
fn next(&mut self) -> Option<&'a str>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a, A> Iterator for std::option::Iter<'a, A>
[src]
type Item = &'a A
fn next(&mut self) -> Option<&'a A>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a, A> Iterator for std::option::IterMut<'a, A>
[src]
type Item = &'a mut A
fn next(&mut self) -> Option<&'a mut A>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a, I, T> Iterator for Cloned<I> where
I: Iterator<Item = &'a T>,
T: 'a + Clone,
[src]
I: Iterator<Item = &'a T>,
T: 'a + Clone,
type Item = T
fn next(&mut self) -> Option<T>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
F: FnMut(B, <Cloned<I> as Iterator>::Item) -> R,
R: Try<Ok = B>,
Cloned<I>: Sized,
[src]
F: FnMut(B, <Cloned<I> as Iterator>::Item) -> R,
R: Try<Ok = B>,
Cloned<I>: Sized,
fn fold<Acc, F>(self, init: Acc, f: F) -> Acc where
F: FnMut(Acc, <Cloned<I> as Iterator>::Item) -> Acc,
[src]
F: FnMut(Acc, <Cloned<I> as Iterator>::Item) -> Acc,
impl<'a, I, T> Iterator for Copied<I> where
I: Iterator<Item = &'a T>,
T: 'a + Copy,
[src]
I: Iterator<Item = &'a T>,
T: 'a + Copy,
type Item = T
fn next(&mut self) -> Option<T>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
F: FnMut(B, <Copied<I> as Iterator>::Item) -> R,
R: Try<Ok = B>,
Copied<I>: Sized,
[src]
F: FnMut(B, <Copied<I> as Iterator>::Item) -> R,
R: Try<Ok = B>,
Copied<I>: Sized,
fn fold<Acc, F>(self, init: Acc, f: F) -> Acc where
F: FnMut(Acc, <Copied<I> as Iterator>::Item) -> Acc,
[src]
F: FnMut(Acc, <Copied<I> as Iterator>::Item) -> Acc,
impl<'a, K> Iterator for std::collections::hash_set::Drain<'a, K>
[src]
impl<'a, K> Iterator for std::collections::hash_set::Iter<'a, K>
[src]
type Item = &'a K
fn next(&mut self) -> Option<&'a K>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a, K, V> Iterator for std::collections::btree_map::Iter<'a, K, V> where
K: 'a,
V: 'a,
[src]
K: 'a,
V: 'a,
type Item = (&'a K, &'a V)
fn next(&mut self) -> Option<(&'a K, &'a V)>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a, K, V> Iterator for std::collections::btree_map::IterMut<'a, K, V> where
K: 'a,
V: 'a,
[src]
K: 'a,
V: 'a,
type Item = (&'a K, &'a mut V)
fn next(&mut self) -> Option<(&'a K, &'a mut V)>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a, K, V> Iterator for std::collections::btree_map::Keys<'a, K, V>
[src]
type Item = &'a K
fn next(&mut self) -> Option<&'a K>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a, K, V> Iterator for std::collections::btree_map::Range<'a, K, V>
[src]
impl<'a, K, V> Iterator for RangeMut<'a, K, V>
[src]
impl<'a, K, V> Iterator for std::collections::btree_map::Values<'a, K, V>
[src]
type Item = &'a V
fn next(&mut self) -> Option<&'a V>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a, K, V> Iterator for std::collections::btree_map::ValuesMut<'a, K, V>
[src]
type Item = &'a mut V
fn next(&mut self) -> Option<&'a mut V>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a, K, V> Iterator for std::collections::hash_map::Drain<'a, K, V>
[src]
type Item = (K, V)
fn next(&mut self) -> Option<(K, V)>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a, K, V> Iterator for std::collections::hash_map::Iter<'a, K, V>
[src]
type Item = (&'a K, &'a V)
fn next(&mut self) -> Option<(&'a K, &'a V)>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a, K, V> Iterator for std::collections::hash_map::IterMut<'a, K, V>
[src]
type Item = (&'a K, &'a mut V)
fn next(&mut self) -> Option<(&'a K, &'a mut V)>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a, K, V> Iterator for std::collections::hash_map::Keys<'a, K, V>
[src]
type Item = &'a K
fn next(&mut self) -> Option<&'a K>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a, K, V> Iterator for std::collections::hash_map::Values<'a, K, V>
[src]
type Item = &'a V
fn next(&mut self) -> Option<&'a V>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a, K, V> Iterator for std::collections::hash_map::ValuesMut<'a, K, V>
[src]
type Item = &'a mut V
fn next(&mut self) -> Option<&'a mut V>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a, P> Iterator for MatchIndices<'a, P> where
P: Pattern<'a>,
[src]
P: Pattern<'a>,
impl<'a, P> Iterator for Matches<'a, P> where
P: Pattern<'a>,
[src]
P: Pattern<'a>,
impl<'a, P> Iterator for RMatchIndices<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
[src]
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
impl<'a, P> Iterator for RMatches<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
[src]
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
impl<'a, P> Iterator for std::str::RSplit<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
[src]
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
impl<'a, P> Iterator for std::str::RSplitN<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
[src]
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
impl<'a, P> Iterator for RSplitTerminator<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
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P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
impl<'a, P> Iterator for std::str::Split<'a, P> where
P: Pattern<'a>,
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P: Pattern<'a>,
impl<'a, P> Iterator for std::str::SplitN<'a, P> where
P: Pattern<'a>,
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P: Pattern<'a>,
impl<'a, P> Iterator for SplitTerminator<'a, P> where
P: Pattern<'a>,
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P: Pattern<'a>,
impl<'a, T> Iterator for std::collections::binary_heap::Iter<'a, T>
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type Item = &'a T
fn next(&mut self) -> Option<&'a T>
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fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T> Iterator for std::collections::btree_set::Difference<'a, T> where
T: Ord,
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T: Ord,
type Item = &'a T
fn next(&mut self) -> Option<&'a T>
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fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T> Iterator for std::collections::btree_set::Intersection<'a, T> where
T: Ord,
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T: Ord,
type Item = &'a T
fn next(&mut self) -> Option<&'a T>
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fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T> Iterator for std::collections::btree_set::Iter<'a, T>
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type Item = &'a T
fn next(&mut self) -> Option<&'a T>
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fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T> Iterator for std::collections::btree_set::Range<'a, T>
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impl<'a, T> Iterator for std::collections::btree_set::SymmetricDifference<'a, T> where
T: Ord,
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T: Ord,
type Item = &'a T
fn next(&mut self) -> Option<&'a T>
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fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T> Iterator for std::collections::btree_set::Union<'a, T> where
T: Ord,
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T: Ord,
type Item = &'a T
fn next(&mut self) -> Option<&'a T>
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fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T> Iterator for std::collections::linked_list::Iter<'a, T>
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type Item = &'a T
fn next(&mut self) -> Option<&'a T>
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fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T> Iterator for std::collections::linked_list::IterMut<'a, T>
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type Item = &'a mut T
fn next(&mut self) -> Option<&'a mut T>
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fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T> Iterator for std::collections::vec_deque::Iter<'a, T>
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type Item = &'a T
fn next(&mut self) -> Option<&'a T>
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fn size_hint(&self) -> (usize, Option<usize>)
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fn fold<Acc, F>(self, accum: Acc, f: F) -> Acc where
F: FnMut(Acc, <Iter<'a, T> as Iterator>::Item) -> Acc,
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F: FnMut(Acc, <Iter<'a, T> as Iterator>::Item) -> Acc,
fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
F: FnMut(B, <Iter<'a, T> as Iterator>::Item) -> R,
R: Try<Ok = B>,
Iter<'a, T>: Sized,
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F: FnMut(B, <Iter<'a, T> as Iterator>::Item) -> R,
R: Try<Ok = B>,
Iter<'a, T>: Sized,
impl<'a, T> Iterator for std::collections::vec_deque::IterMut<'a, T>
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type Item = &'a mut T
fn next(&mut self) -> Option<&'a mut T>
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fn size_hint(&self) -> (usize, Option<usize>)
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fn fold<Acc, F>(self, accum: Acc, f: F) -> Acc where
F: FnMut(Acc, <IterMut<'a, T> as Iterator>::Item) -> Acc,
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F: FnMut(Acc, <IterMut<'a, T> as Iterator>::Item) -> Acc,
impl<'a, T> Iterator for std::result::Iter<'a, T>
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type Item = &'a T
fn next(&mut self) -> Option<&'a T>
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fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T> Iterator for std::result::IterMut<'a, T>
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type Item = &'a mut T
fn next(&mut self) -> Option<&'a mut T>
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fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T> Iterator for Chunks<'a, T>
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type Item = &'a [T]
fn next(&mut self) -> Option<&'a [T]>
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fn size_hint(&self) -> (usize, Option<usize>)
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fn count(self) -> usize
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fn nth(&mut self, n: usize) -> Option<<Chunks<'a, T> as Iterator>::Item>
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fn last(self) -> Option<<Chunks<'a, T> as Iterator>::Item>
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impl<'a, T> Iterator for ChunksExact<'a, T>
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type Item = &'a [T]
fn next(&mut self) -> Option<&'a [T]>
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fn size_hint(&self) -> (usize, Option<usize>)
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fn count(self) -> usize
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fn nth(&mut self, n: usize) -> Option<<ChunksExact<'a, T> as Iterator>::Item>
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fn last(self) -> Option<<ChunksExact<'a, T> as Iterator>::Item>
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impl<'a, T> Iterator for ChunksExactMut<'a, T>
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type Item = &'a mut [T]
fn next(&mut self) -> Option<&'a mut [T]>
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fn size_hint(&self) -> (usize, Option<usize>)
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fn count(self) -> usize
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fn nth(&mut self, n: usize) -> Option<&'a mut [T]>
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fn last(self) -> Option<<ChunksExactMut<'a, T> as Iterator>::Item>
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impl<'a, T> Iterator for ChunksMut<'a, T>
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type Item = &'a mut [T]
fn next(&mut self) -> Option<&'a mut [T]>
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fn size_hint(&self) -> (usize, Option<usize>)
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fn count(self) -> usize
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fn nth(&mut self, n: usize) -> Option<&'a mut [T]>
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fn last(self) -> Option<<ChunksMut<'a, T> as Iterator>::Item>
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impl<'a, T> Iterator for std::slice::Iter<'a, T>
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type Item = &'a T
fn next(&mut self) -> Option<&'a T>
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fn size_hint(&self) -> (usize, Option<usize>)
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fn count(self) -> usize
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fn nth(&mut self, n: usize) -> Option<&'a T>
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fn last(self) -> Option<&'a T>
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fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
F: FnMut(B, <Iter<'a, T> as Iterator>::Item) -> R,
R: Try<Ok = B>,
Iter<'a, T>: Sized,
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F: FnMut(B, <Iter<'a, T> as Iterator>::Item) -> R,
R: Try<Ok = B>,
Iter<'a, T>: Sized,
fn fold<Acc, Fold>(self, init: Acc, f: Fold) -> Acc where
Fold: FnMut(Acc, <Iter<'a, T> as Iterator>::Item) -> Acc,
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Fold: FnMut(Acc, <Iter<'a, T> as Iterator>::Item) -> Acc,
fn position<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(<Iter<'a, T> as Iterator>::Item) -> bool,
Iter<'a, T>: Sized,
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P: FnMut(<Iter<'a, T> as Iterator>::Item) -> bool,
Iter<'a, T>: Sized,
fn rposition<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(<Iter<'a, T> as Iterator>::Item) -> bool,
Iter<'a, T>: Sized,
Iter<'a, T>: ExactSizeIterator,
Iter<'a, T>: DoubleEndedIterator,
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P: FnMut(<Iter<'a, T> as Iterator>::Item) -> bool,
Iter<'a, T>: Sized,
Iter<'a, T>: ExactSizeIterator,
Iter<'a, T>: DoubleEndedIterator,
fn is_sorted_by<F>(self, compare: F) -> bool where
F: FnMut(&<Iter<'a, T> as Iterator>::Item, &<Iter<'a, T> as Iterator>::Item) -> Option<Ordering>,
Iter<'a, T>: Sized,
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F: FnMut(&<Iter<'a, T> as Iterator>::Item, &<Iter<'a, T> as Iterator>::Item) -> Option<Ordering>,
Iter<'a, T>: Sized,
impl<'a, T> Iterator for std::slice::IterMut<'a, T>
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type Item = &'a mut T
fn next(&mut self) -> Option<&'a mut T>
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fn size_hint(&self) -> (usize, Option<usize>)
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fn count(self) -> usize
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fn nth(&mut self, n: usize) -> Option<&'a mut T>
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fn last(self) -> Option<&'a mut T>
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fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
F: FnMut(B, <IterMut<'a, T> as Iterator>::Item) -> R,
R: Try<Ok = B>,
IterMut<'a, T>: Sized,
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F: FnMut(B, <IterMut<'a, T> as Iterator>::Item) -> R,
R: Try<Ok = B>,
IterMut<'a, T>: Sized,
fn fold<Acc, Fold>(self, init: Acc, f: Fold) -> Acc where
Fold: FnMut(Acc, <IterMut<'a, T> as Iterator>::Item) -> Acc,
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Fold: FnMut(Acc, <IterMut<'a, T> as Iterator>::Item) -> Acc,
fn position<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(<IterMut<'a, T> as Iterator>::Item) -> bool,
IterMut<'a, T>: Sized,
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P: FnMut(<IterMut<'a, T> as Iterator>::Item) -> bool,
IterMut<'a, T>: Sized,
fn rposition<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(<IterMut<'a, T> as Iterator>::Item) -> bool,
IterMut<'a, T>: Sized,
IterMut<'a, T>: ExactSizeIterator,
IterMut<'a, T>: DoubleEndedIterator,
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P: FnMut(<IterMut<'a, T> as Iterator>::Item) -> bool,
IterMut<'a, T>: Sized,
IterMut<'a, T>: ExactSizeIterator,
IterMut<'a, T>: DoubleEndedIterator,
impl<'a, T> Iterator for RChunks<'a, T>
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type Item = &'a [T]
fn next(&mut self) -> Option<&'a [T]>
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fn size_hint(&self) -> (usize, Option<usize>)
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fn count(self) -> usize
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fn nth(&mut self, n: usize) -> Option<<RChunks<'a, T> as Iterator>::Item>
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fn last(self) -> Option<<RChunks<'a, T> as Iterator>::Item>
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impl<'a, T> Iterator for RChunksExact<'a, T>
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type Item = &'a [T]
fn next(&mut self) -> Option<&'a [T]>
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fn size_hint(&self) -> (usize, Option<usize>)
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fn count(self) -> usize
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fn nth(&mut self, n: usize) -> Option<<RChunksExact<'a, T> as Iterator>::Item>
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fn last(self) -> Option<<RChunksExact<'a, T> as Iterator>::Item>
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impl<'a, T> Iterator for RChunksExactMut<'a, T>
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type Item = &'a mut [T]
fn next(&mut self) -> Option<&'a mut [T]>
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fn size_hint(&self) -> (usize, Option<usize>)
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fn count(self) -> usize
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fn nth(&mut self, n: usize) -> Option<&'a mut [T]>
[src]
fn last(self) -> Option<<RChunksExactMut<'a, T> as Iterator>::Item>
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impl<'a, T> Iterator for RChunksMut<'a, T>
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type Item = &'a mut [T]
fn next(&mut self) -> Option<&'a mut [T]>
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fn size_hint(&self) -> (usize, Option<usize>)
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fn count(self) -> usize
[src]
fn nth(&mut self, n: usize) -> Option<&'a mut [T]>
[src]
fn last(self) -> Option<<RChunksMut<'a, T> as Iterator>::Item>
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impl<'a, T> Iterator for Windows<'a, T>
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type Item = &'a [T]
fn next(&mut self) -> Option<&'a [T]>
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fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn count(self) -> usize
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fn nth(&mut self, n: usize) -> Option<<Windows<'a, T> as Iterator>::Item>
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fn last(self) -> Option<<Windows<'a, T> as Iterator>::Item>
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impl<'a, T> Iterator for std::sync::mpsc::Iter<'a, T>
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impl<'a, T> Iterator for TryIter<'a, T>
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impl<'a, T, P> Iterator for std::slice::RSplit<'a, T, P> where
P: FnMut(&T) -> bool,
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P: FnMut(&T) -> bool,
type Item = &'a [T]
fn next(&mut self) -> Option<&'a [T]>
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fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T, P> Iterator for RSplitMut<'a, T, P> where
P: FnMut(&T) -> bool,
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P: FnMut(&T) -> bool,
type Item = &'a mut [T]
fn next(&mut self) -> Option<&'a mut [T]>
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fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T, P> Iterator for std::slice::RSplitN<'a, T, P> where
P: FnMut(&T) -> bool,
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P: FnMut(&T) -> bool,
type Item = &'a [T]
fn next(&mut self) -> Option<&'a [T]>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T, P> Iterator for RSplitNMut<'a, T, P> where
P: FnMut(&T) -> bool,
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P: FnMut(&T) -> bool,
type Item = &'a mut [T]
fn next(&mut self) -> Option<&'a mut [T]>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T, P> Iterator for std::slice::Split<'a, T, P> where
P: FnMut(&T) -> bool,
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P: FnMut(&T) -> bool,
type Item = &'a [T]
fn next(&mut self) -> Option<&'a [T]>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T, P> Iterator for SplitMut<'a, T, P> where
P: FnMut(&T) -> bool,
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P: FnMut(&T) -> bool,
type Item = &'a mut [T]
fn next(&mut self) -> Option<&'a mut [T]>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T, P> Iterator for std::slice::SplitN<'a, T, P> where
P: FnMut(&T) -> bool,
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P: FnMut(&T) -> bool,
type Item = &'a [T]
fn next(&mut self) -> Option<&'a [T]>
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fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T, P> Iterator for SplitNMut<'a, T, P> where
P: FnMut(&T) -> bool,
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P: FnMut(&T) -> bool,
type Item = &'a mut [T]
fn next(&mut self) -> Option<&'a mut [T]>
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fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T, S> Iterator for std::collections::hash_set::Difference<'a, T, S> where
T: Eq + Hash,
S: BuildHasher,
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T: Eq + Hash,
S: BuildHasher,
type Item = &'a T
fn next(&mut self) -> Option<&'a T>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T, S> Iterator for std::collections::hash_set::Intersection<'a, T, S> where
T: Eq + Hash,
S: BuildHasher,
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T: Eq + Hash,
S: BuildHasher,
type Item = &'a T
fn next(&mut self) -> Option<&'a T>
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fn size_hint(&self) -> (usize, Option<usize>)
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impl<'a, T, S> Iterator for std::collections::hash_set::SymmetricDifference<'a, T, S> where
T: Eq + Hash,
S: BuildHasher,
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T: Eq + Hash,
S: BuildHasher,
type Item = &'a T
fn next(&mut self) -> Option<&'a T>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<'a, T, S> Iterator for std::collections::hash_set::Union<'a, T, S> where
T: Eq + Hash,
S: BuildHasher,
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T: Eq + Hash,
S: BuildHasher,
type Item = &'a T
fn next(&mut self) -> Option<&'a T>
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fn size_hint(&self) -> (usize, Option<usize>)
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impl<A> Iterator for Repeat<A> where
A: Clone,
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A: Clone,
impl<A> Iterator for std::ops::Range<A> where
A: Step,
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A: Step,
type Item = A
fn next(&mut self) -> Option<A>
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fn size_hint(&self) -> (usize, Option<usize>)
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fn nth(&mut self, n: usize) -> Option<A>
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fn last(self) -> Option<A>
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fn min(self) -> Option<A>
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fn max(self) -> Option<A>
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impl<A> Iterator for RangeFrom<A> where
A: Step,
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A: Step,
type Item = A
fn next(&mut self) -> Option<A>
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fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn nth(&mut self, n: usize) -> Option<A>
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impl<A> Iterator for RangeInclusive<A> where
A: Step,
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A: Step,
type Item = A
fn next(&mut self) -> Option<A>
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fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn nth(&mut self, n: usize) -> Option<A>
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fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
F: FnMut(B, <RangeInclusive<A> as Iterator>::Item) -> R,
R: Try<Ok = B>,
RangeInclusive<A>: Sized,
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F: FnMut(B, <RangeInclusive<A> as Iterator>::Item) -> R,
R: Try<Ok = B>,
RangeInclusive<A>: Sized,
fn last(self) -> Option<A>
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fn min(self) -> Option<A>
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fn max(self) -> Option<A>
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impl<A> Iterator for std::option::IntoIter<A>
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impl<A, B> Iterator for Chain<A, B> where
A: Iterator,
B: Iterator<Item = <A as Iterator>::Item>,
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A: Iterator,
B: Iterator<Item = <A as Iterator>::Item>,
type Item = <A as Iterator>::Item
fn next(&mut self) -> Option<<A as Iterator>::Item>
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fn count(self) -> usize
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fn try_fold<Acc, F, R>(&mut self, init: Acc, f: F) -> R where
F: FnMut(Acc, <Chain<A, B> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Chain<A, B>: Sized,
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F: FnMut(Acc, <Chain<A, B> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Chain<A, B>: Sized,
fn fold<Acc, F>(self, init: Acc, f: F) -> Acc where
F: FnMut(Acc, <Chain<A, B> as Iterator>::Item) -> Acc,
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F: FnMut(Acc, <Chain<A, B> as Iterator>::Item) -> Acc,
fn nth(&mut self, n: usize) -> Option<<A as Iterator>::Item>
[src]
fn find<P>(&mut self, predicate: P) -> Option<<Chain<A, B> as Iterator>::Item> where
P: FnMut(&<Chain<A, B> as Iterator>::Item) -> bool,
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P: FnMut(&<Chain<A, B> as Iterator>::Item) -> bool,
fn last(self) -> Option<<A as Iterator>::Item>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<A, B> Iterator for Zip<A, B> where
A: Iterator,
B: Iterator,
[src]
A: Iterator,
B: Iterator,
type Item = (<A as Iterator>::Item, <B as Iterator>::Item)
fn next(&mut self) -> Option<<Zip<A, B> as Iterator>::Item>
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fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn nth(&mut self, n: usize) -> Option<<Zip<A, B> as Iterator>::Item>
[src]
impl<A, F> Iterator for OnceWith<F> where
F: FnOnce() -> A,
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F: FnOnce() -> A,
impl<A, F> Iterator for RepeatWith<F> where
F: FnMut() -> A,
[src]
F: FnMut() -> A,
impl<B, I, F> Iterator for FilterMap<I, F> where
F: FnMut(<I as Iterator>::Item) -> Option<B>,
I: Iterator,
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F: FnMut(<I as Iterator>::Item) -> Option<B>,
I: Iterator,
type Item = B
fn next(&mut self) -> Option<B>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <FilterMap<I, F> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
FilterMap<I, F>: Sized,
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Fold: FnMut(Acc, <FilterMap<I, F> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
FilterMap<I, F>: Sized,
fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <FilterMap<I, F> as Iterator>::Item) -> Acc,
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Fold: FnMut(Acc, <FilterMap<I, F> as Iterator>::Item) -> Acc,
impl<B, I, F> Iterator for Map<I, F> where
F: FnMut(<I as Iterator>::Item) -> B,
I: Iterator,
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F: FnMut(<I as Iterator>::Item) -> B,
I: Iterator,
type Item = B
fn next(&mut self) -> Option<B>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn try_fold<Acc, G, R>(&mut self, init: Acc, g: G) -> R where
G: FnMut(Acc, <Map<I, F> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Map<I, F>: Sized,
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G: FnMut(Acc, <Map<I, F> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Map<I, F>: Sized,
fn fold<Acc, G>(self, init: Acc, g: G) -> Acc where
G: FnMut(Acc, <Map<I, F> as Iterator>::Item) -> Acc,
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G: FnMut(Acc, <Map<I, F> as Iterator>::Item) -> Acc,
impl<B, I, St, F> Iterator for Scan<I, St, F> where
F: FnMut(&mut St, <I as Iterator>::Item) -> Option<B>,
I: Iterator,
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F: FnMut(&mut St, <I as Iterator>::Item) -> Option<B>,
I: Iterator,
type Item = B
fn next(&mut self) -> Option<B>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <Scan<I, St, F> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Scan<I, St, F>: Sized,
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Fold: FnMut(Acc, <Scan<I, St, F> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Scan<I, St, F>: Sized,
impl<B: BufRead> Iterator for std::io::Lines<B>
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impl<B: BufRead> Iterator for std::io::Split<B>
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impl<I> Iterator for Box<I> where
I: Iterator + ?Sized,
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I: Iterator + ?Sized,
type Item = <I as Iterator>::Item
fn next(&mut self) -> Option<<I as Iterator>::Item>
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fn size_hint(&self) -> (usize, Option<usize>)
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fn nth(&mut self, n: usize) -> Option<<I as Iterator>::Item>
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impl<I> Iterator for DecodeUtf16<I> where
I: Iterator<Item = u16>,
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I: Iterator<Item = u16>,
type Item = Result<char, DecodeUtf16Error>
fn next(&mut self) -> Option<Result<char, DecodeUtf16Error>>
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fn size_hint(&self) -> (usize, Option<usize>)
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impl<I> Iterator for Cycle<I> where
I: Clone + Iterator,
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I: Clone + Iterator,
type Item = <I as Iterator>::Item
fn next(&mut self) -> Option<<I as Iterator>::Item>
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fn size_hint(&self) -> (usize, Option<usize>)
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impl<I> Iterator for Enumerate<I> where
I: Iterator,
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I: Iterator,
type Item = (usize, <I as Iterator>::Item)
fn next(&mut self) -> Option<(usize, <I as Iterator>::Item)>
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Overflow Behavior
The method does no guarding against overflows, so enumerating more than
usize::MAX
elements either produces the wrong result or panics. If
debug assertions are enabled, a panic is guaranteed.
Panics
Might panic if the index of the element overflows a usize
.
fn size_hint(&self) -> (usize, Option<usize>)
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fn nth(&mut self, n: usize) -> Option<(usize, <I as Iterator>::Item)>
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fn count(self) -> usize
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fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <Enumerate<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Enumerate<I>: Sized,
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Fold: FnMut(Acc, <Enumerate<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Enumerate<I>: Sized,
fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <Enumerate<I> as Iterator>::Item) -> Acc,
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Fold: FnMut(Acc, <Enumerate<I> as Iterator>::Item) -> Acc,
impl<I> Iterator for Fuse<I> where
I: FusedIterator,
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I: FusedIterator,
fn next(&mut self) -> Option<<I as Iterator>::Item>
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fn nth(&mut self, n: usize) -> Option<<I as Iterator>::Item>
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fn last(self) -> Option<<I as Iterator>::Item>
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fn count(self) -> usize
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fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <Fuse<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Fuse<I>: Sized,
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Fold: FnMut(Acc, <Fuse<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Fuse<I>: Sized,
fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <Fuse<I> as Iterator>::Item) -> Acc,
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Fold: FnMut(Acc, <Fuse<I> as Iterator>::Item) -> Acc,
impl<I> Iterator for Fuse<I> where
I: Iterator,
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I: Iterator,
type Item = <I as Iterator>::Item
default fn next(&mut self) -> Option<<I as Iterator>::Item>
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default fn nth(&mut self, n: usize) -> Option<<I as Iterator>::Item>
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default fn last(self) -> Option<<I as Iterator>::Item>
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default fn count(self) -> usize
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default fn size_hint(&self) -> (usize, Option<usize>)
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default fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <Fuse<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Fuse<I>: Sized,
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Fold: FnMut(Acc, <Fuse<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Fuse<I>: Sized,
default fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <Fuse<I> as Iterator>::Item) -> Acc,
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Fold: FnMut(Acc, <Fuse<I> as Iterator>::Item) -> Acc,
impl<I> Iterator for Peekable<I> where
I: Iterator,
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I: Iterator,
type Item = <I as Iterator>::Item
fn next(&mut self) -> Option<<I as Iterator>::Item>
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fn count(self) -> usize
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fn nth(&mut self, n: usize) -> Option<<I as Iterator>::Item>
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fn last(self) -> Option<<I as Iterator>::Item>
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fn size_hint(&self) -> (usize, Option<usize>)
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fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
F: FnMut(B, <Peekable<I> as Iterator>::Item) -> R,
R: Try<Ok = B>,
Peekable<I>: Sized,
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F: FnMut(B, <Peekable<I> as Iterator>::Item) -> R,
R: Try<Ok = B>,
Peekable<I>: Sized,
fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <Peekable<I> as Iterator>::Item) -> Acc,
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Fold: FnMut(Acc, <Peekable<I> as Iterator>::Item) -> Acc,
impl<I> Iterator for Rev<I> where
I: DoubleEndedIterator,
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I: DoubleEndedIterator,
type Item = <I as Iterator>::Item
fn next(&mut self) -> Option<<I as Iterator>::Item>
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fn size_hint(&self) -> (usize, Option<usize>)
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fn nth(&mut self, n: usize) -> Option<<I as Iterator>::Item>
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fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
F: FnMut(B, <Rev<I> as Iterator>::Item) -> R,
R: Try<Ok = B>,
Rev<I>: Sized,
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F: FnMut(B, <Rev<I> as Iterator>::Item) -> R,
R: Try<Ok = B>,
Rev<I>: Sized,
fn fold<Acc, F>(self, init: Acc, f: F) -> Acc where
F: FnMut(Acc, <Rev<I> as Iterator>::Item) -> Acc,
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F: FnMut(Acc, <Rev<I> as Iterator>::Item) -> Acc,
fn find<P>(&mut self, predicate: P) -> Option<<Rev<I> as Iterator>::Item> where
P: FnMut(&<Rev<I> as Iterator>::Item) -> bool,
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P: FnMut(&<Rev<I> as Iterator>::Item) -> bool,
fn rposition<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(<Rev<I> as Iterator>::Item) -> bool,
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P: FnMut(<Rev<I> as Iterator>::Item) -> bool,
impl<I> Iterator for Skip<I> where
I: Iterator,
[src]
I: Iterator,
type Item = <I as Iterator>::Item
fn next(&mut self) -> Option<<I as Iterator>::Item>
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fn nth(&mut self, n: usize) -> Option<<I as Iterator>::Item>
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fn count(self) -> usize
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fn last(self) -> Option<<I as Iterator>::Item>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <Skip<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Skip<I>: Sized,
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Fold: FnMut(Acc, <Skip<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Skip<I>: Sized,
fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <Skip<I> as Iterator>::Item) -> Acc,
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Fold: FnMut(Acc, <Skip<I> as Iterator>::Item) -> Acc,
impl<I> Iterator for StepBy<I> where
I: Iterator,
[src]
I: Iterator,
type Item = <I as Iterator>::Item
fn next(&mut self) -> Option<<StepBy<I> as Iterator>::Item>
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fn size_hint(&self) -> (usize, Option<usize>)
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fn nth(&mut self, n: usize) -> Option<<StepBy<I> as Iterator>::Item>
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impl<I> Iterator for Take<I> where
I: Iterator,
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I: Iterator,
type Item = <I as Iterator>::Item
fn next(&mut self) -> Option<<I as Iterator>::Item>
[src]
fn nth(&mut self, n: usize) -> Option<<I as Iterator>::Item>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <Take<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Take<I>: Sized,
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Fold: FnMut(Acc, <Take<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Take<I>: Sized,
impl<I, F> Iterator for Inspect<I, F> where
F: FnMut(&<I as Iterator>::Item),
I: Iterator,
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F: FnMut(&<I as Iterator>::Item),
I: Iterator,
type Item = <I as Iterator>::Item
fn next(&mut self) -> Option<<I as Iterator>::Item>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <Inspect<I, F> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Inspect<I, F>: Sized,
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Fold: FnMut(Acc, <Inspect<I, F> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Inspect<I, F>: Sized,
fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <Inspect<I, F> as Iterator>::Item) -> Acc,
[src]
Fold: FnMut(Acc, <Inspect<I, F> as Iterator>::Item) -> Acc,
impl<I, P> Iterator for Filter<I, P> where
I: Iterator,
P: FnMut(&<I as Iterator>::Item) -> bool,
[src]
I: Iterator,
P: FnMut(&<I as Iterator>::Item) -> bool,
type Item = <I as Iterator>::Item
fn next(&mut self) -> Option<<I as Iterator>::Item>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn count(self) -> usize
[src]
fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <Filter<I, P> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Filter<I, P>: Sized,
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Fold: FnMut(Acc, <Filter<I, P> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Filter<I, P>: Sized,
fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <Filter<I, P> as Iterator>::Item) -> Acc,
[src]
Fold: FnMut(Acc, <Filter<I, P> as Iterator>::Item) -> Acc,
impl<I, P> Iterator for SkipWhile<I, P> where
I: Iterator,
P: FnMut(&<I as Iterator>::Item) -> bool,
[src]
I: Iterator,
P: FnMut(&<I as Iterator>::Item) -> bool,
type Item = <I as Iterator>::Item
fn next(&mut self) -> Option<<I as Iterator>::Item>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <SkipWhile<I, P> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
SkipWhile<I, P>: Sized,
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Fold: FnMut(Acc, <SkipWhile<I, P> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
SkipWhile<I, P>: Sized,
fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <SkipWhile<I, P> as Iterator>::Item) -> Acc,
[src]
Fold: FnMut(Acc, <SkipWhile<I, P> as Iterator>::Item) -> Acc,
impl<I, P> Iterator for TakeWhile<I, P> where
I: Iterator,
P: FnMut(&<I as Iterator>::Item) -> bool,
[src]
I: Iterator,
P: FnMut(&<I as Iterator>::Item) -> bool,
type Item = <I as Iterator>::Item
fn next(&mut self) -> Option<<I as Iterator>::Item>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <TakeWhile<I, P> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
TakeWhile<I, P>: Sized,
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Fold: FnMut(Acc, <TakeWhile<I, P> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
TakeWhile<I, P>: Sized,
impl<I, U> Iterator for Flatten<I> where
I: Iterator,
U: Iterator,
<I as Iterator>::Item: IntoIterator,
<<I as Iterator>::Item as IntoIterator>::IntoIter == U,
<<I as Iterator>::Item as IntoIterator>::Item == <U as Iterator>::Item,
[src]
I: Iterator,
U: Iterator,
<I as Iterator>::Item: IntoIterator,
<<I as Iterator>::Item as IntoIterator>::IntoIter == U,
<<I as Iterator>::Item as IntoIterator>::Item == <U as Iterator>::Item,
type Item = <U as Iterator>::Item
fn next(&mut self) -> Option<<U as Iterator>::Item>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <Flatten<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Flatten<I>: Sized,
[src]
Fold: FnMut(Acc, <Flatten<I> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
Flatten<I>: Sized,
fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <Flatten<I> as Iterator>::Item) -> Acc,
[src]
Fold: FnMut(Acc, <Flatten<I> as Iterator>::Item) -> Acc,
impl<I, U, F> Iterator for FlatMap<I, U, F> where
F: FnMut(<I as Iterator>::Item) -> U,
I: Iterator,
U: IntoIterator,
[src]
F: FnMut(<I as Iterator>::Item) -> U,
I: Iterator,
U: IntoIterator,
type Item = <U as IntoIterator>::Item
fn next(&mut self) -> Option<<U as IntoIterator>::Item>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Fold: FnMut(Acc, <FlatMap<I, U, F> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
FlatMap<I, U, F>: Sized,
[src]
Fold: FnMut(Acc, <FlatMap<I, U, F> as Iterator>::Item) -> R,
R: Try<Ok = Acc>,
FlatMap<I, U, F>: Sized,
fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc where
Fold: FnMut(Acc, <FlatMap<I, U, F> as Iterator>::Item) -> Acc,
[src]
Fold: FnMut(Acc, <FlatMap<I, U, F> as Iterator>::Item) -> Acc,
impl<K> Iterator for std::collections::hash_set::IntoIter<K>
[src]
impl<K, V> Iterator for std::collections::btree_map::IntoIter<K, V>
[src]
type Item = (K, V)
fn next(&mut self) -> Option<(K, V)>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<K, V> Iterator for std::collections::hash_map::IntoIter<K, V>
[src]
type Item = (K, V)
fn next(&mut self) -> Option<(K, V)>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
impl<R: Read> Iterator for std::io::Bytes<R>
[src]
impl<T> Iterator for std::collections::binary_heap::IntoIter<T>
[src]
impl<T> Iterator for std::collections::btree_set::IntoIter<T>
[src]
impl<T> Iterator for std::collections::linked_list::IntoIter<T>
[src]
impl<T> Iterator for std::collections::vec_deque::IntoIter<T>
[src]
impl<T> Iterator for Empty<T>
[src]
impl<T> Iterator for Once<T>
[src]
impl<T> Iterator for std::result::IntoIter<T>
[src]
impl<T> Iterator for std::sync::mpsc::IntoIter<T>
[src]
impl<T> Iterator for std::vec::IntoIter<T>
[src]
type Item = T
fn next(&mut self) -> Option<T>
[src]
fn size_hint(&self) -> (usize, Option<usize>)
[src]
fn count(self) -> usize
[src]
impl<T, F> Iterator for FromFn<F> where
F: FnMut() -> Option<T>,
[src]
F: FnMut() -> Option<T>,
impl<T, F> Iterator for Successors<T, F> where
F: FnMut(&T) -> Option<T>,
[src]
F: FnMut(&T) -> Option<T>,