Trait std::iter::Iterator
[−]
[src]
pub trait Iterator { type Item; fn next(&mut self) -> Option<Self::Item>; fn size_hint(&self) -> (usize, Option<usize>) { ... } fn count(self) -> usize { ... } fn last(self) -> Option<Self::Item> { ... } fn nth(&mut self, n: usize) -> Option<Self::Item> { ... } fn chain<U>(self, other: U) -> Chain<Self, U::IntoIter> where U: IntoIterator<Item=Self::Item> { ... } fn zip<U>(self, other: U) -> Zip<Self, U::IntoIter> where U: IntoIterator { ... } fn map<B, F>(self, f: F) -> Map<Self, F> where F: FnMut(Self::Item) -> B { ... } fn filter<P>(self, predicate: P) -> Filter<Self, P> where P: FnMut(&Self::Item) -> bool { ... } fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F> where F: FnMut(Self::Item) -> Option<B> { ... } fn enumerate(self) -> Enumerate<Self> { ... } fn peekable(self) -> Peekable<Self> { ... } fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P> where P: FnMut(&Self::Item) -> bool { ... } fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P> where P: FnMut(&Self::Item) -> bool { ... } fn skip(self, n: usize) -> Skip<Self> { ... } fn take(self, n: usize) -> Take<Self> { ... } fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F> where F: FnMut(&mut St, Self::Item) -> Option<B> { ... } fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F> where U: IntoIterator, F: FnMut(Self::Item) -> U { ... } fn fuse(self) -> Fuse<Self> { ... } fn inspect<F>(self, f: F) -> Inspect<Self, F> where F: FnMut(&Self::Item) -> () { ... } fn by_ref(&mut self) -> &mut Self { ... } fn collect<B>(self) -> B where B: FromIterator<Self::Item> { ... } fn partition<B, F>(self, f: F) -> (B, B) where B: Default + Extend<Self::Item>, F: FnMut(&Self::Item) -> bool { ... } fn fold<B, F>(self, init: B, f: F) -> B where F: FnMut(B, Self::Item) -> B { ... } fn all<F>(&mut self, f: F) -> bool where F: FnMut(Self::Item) -> bool { ... } fn any<F>(&mut self, f: F) -> bool where F: FnMut(Self::Item) -> bool { ... } fn find<P>(&mut self, predicate: P) -> Option<Self::Item> where P: FnMut(&Self::Item) -> bool { ... } fn position<P>(&mut self, predicate: P) -> Option<usize> where P: FnMut(Self::Item) -> bool { ... } fn rposition<P>(&mut self, predicate: P) -> Option<usize> where Self: ExactSizeIterator + DoubleEndedIterator, P: FnMut(Self::Item) -> bool { ... } fn max(self) -> Option<Self::Item> where Self::Item: Ord { ... } fn min(self) -> Option<Self::Item> where Self::Item: Ord { ... } fn max_by<B, F>(self, f: F) -> Option<Self::Item> where B: Ord, F: FnMut(&Self::Item) -> B { ... } fn max_by_key<B, F>(self, f: F) -> Option<Self::Item> where F: FnMut(&Self::Item) -> B, B: Ord { ... } fn min_by<B, F>(self, f: F) -> Option<Self::Item> where F: FnMut(&Self::Item) -> B, B: Ord { ... } fn min_by_key<B, F>(self, f: F) -> Option<Self::Item> where B: Ord, F: FnMut(&Self::Item) -> B { ... } fn rev(self) -> Rev<Self> where Self: DoubleEndedIterator { ... } fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB) where Self: Iterator<Item=(A, B)>, FromA: Default + Extend<A>, FromB: Default + Extend<B> { ... } fn cloned<'a, T>(self) -> Cloned<Self> where Self: Iterator<Item=&'a T>, T: 'a + Clone { ... } fn cycle(self) -> Cycle<Self> where Self: Clone { ... } fn sum<S>(self) -> S where S: Add<Self::Item, Output=S> + Zero { ... } fn product<P>(self) -> P where P: Mul<Self::Item, Output=P> + One { ... } fn cmp<I>(self, other: I) -> Ordering where I: IntoIterator<Item=Self::Item>, Self::Item: Ord { ... } fn partial_cmp<I>(self, other: I) -> Option<Ordering> where I: IntoIterator, Self::Item: PartialOrd<I::Item> { ... } fn eq<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialEq<I::Item> { ... } fn ne<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialEq<I::Item> { ... } fn lt<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item> { ... } fn le<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item> { ... } fn gt<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item> { ... } fn ge<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item> { ... } }
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());
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());
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 one 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());
Returning None
for an upper bound:
// an infinite iterator has no upper bound let iter = 0..; assert_eq!((0, None), iter.size_hint());
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);
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));
fn nth(&mut self, n: usize) -> Option<Self::Item>
Consumes the n
first elements of the iterator, then returns the
next()
one.
This method will evaluate the iterator n
times, discarding those elements.
After it does so, it will call next()
and return its value.
Like most indexing operations, the count starts from zero, so nth(0)
returns the first value, nth(1)
the second, and so on.
nth()
will return None
if n
is larger than the length of the
iterator.
Examples
Basic usage:
let a = [1, 2, 3]; assert_eq!(a.iter().nth(1), Some(&2));
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);
Returning None
if there are less than n
elements:
let a = [1, 2, 3]; assert_eq!(a.iter().nth(10), None);
fn chain<U>(self, other: U) -> Chain<Self, U::IntoIter> where 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);
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);
fn zip<U>(self, other: U) -> Zip<Self, U::IntoIter> where 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.
When either iterator returns None
, all further calls to next()
will return None
.
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);
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);
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]);
fn map<B, F>(self, f: F) -> Map<Self, F> where F: FnMut(Self::Item) -> B
Takes a closure and creates an iterator which calls that closure on each element.
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.into_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);
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); }
fn filter<P>(self, predicate: P) -> Filter<Self, P> where P: FnMut(&Self::Item) -> bool
Creates an iterator which uses a closure to determine if an element should be yielded.
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.into_iter().filter(|x| x.is_positive()); assert_eq!(iter.next(), Some(&1)); assert_eq!(iter.next(), Some(&2)); assert_eq!(iter.next(), None);
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.into_iter().filter(|x| **x > 1); // need two *s! assert_eq!(iter.next(), Some(&2)); assert_eq!(iter.next(), None);
It's common to instead use destructuring on the argument to strip away one:
let a = [0, 1, 2]; let mut iter = a.into_iter().filter(|&x| *x > 1); // both & and * assert_eq!(iter.next(), Some(&2)); assert_eq!(iter.next(), None);
or both:
let a = [0, 1, 2]; let mut iter = a.into_iter().filter(|&&x| x > 1); // two &s assert_eq!(iter.next(), Some(&2)); assert_eq!(iter.next(), None);
of these layers.
fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F> where F: FnMut(Self::Item) -> Option<B>
Creates an iterator that both filters and maps.
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()
.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", "2", "lol"]; let mut iter = a.iter().filter_map(|s| s.parse().ok()); assert_eq!(iter.next(), Some(1)); assert_eq!(iter.next(), Some(2)); assert_eq!(iter.next(), None);
Here's the same example, but with filter()
and map()
:
let a = ["1", "2", "lol"]; let mut iter = a.iter() .map(|s| s.parse().ok()) .filter(|s| s.is_some()); assert_eq!(iter.next(), Some(Some(1))); assert_eq!(iter.next(), Some(Some(2))); assert_eq!(iter.next(), None);
There's an extra layer of Some
in there.
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 = [1, 2, 3]; let mut iter = a.iter().enumerate(); assert_eq!(iter.next(), Some((0, &1))); assert_eq!(iter.next(), Some((1, &2))); assert_eq!(iter.next(), Some((2, &3))); assert_eq!(iter.next(), None);
fn peekable(self) -> Peekable<Self>
Creates an iterator which can look at the next()
element without
consuming it.
Adds a peek()
method to an iterator. See its documentation for
more information.
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);
fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P> where P: FnMut(&Self::Item) -> bool
Creates an iterator that skip()
s elements based on a predicate.
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.into_iter().skip_while(|x| x.is_negative()); assert_eq!(iter.next(), Some(&0)); assert_eq!(iter.next(), Some(&1)); assert_eq!(iter.next(), None);
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.into_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);
Stopping after an initial false
:
let a = [-1, 0, 1, -2]; let mut iter = a.into_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);
fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P> where P: FnMut(&Self::Item) -> bool
Creates an iterator that yields elements based on a predicate.
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.into_iter().take_while(|x| x.is_negative()); assert_eq!(iter.next(), Some(&-1)); assert_eq!(iter.next(), None);
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.into_iter().take_while(|x| **x < 0); // need two *s! assert_eq!(iter.next(), Some(&-1)); assert_eq!(iter.next(), None);
Stopping after an initial false
:
let a = [-1, 0, 1, -2]; let mut iter = a.into_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);
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.
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);
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);
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);
fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F> where F: FnMut(&mut St, Self::Item) -> Option<B>
An iterator adaptor similar to fold()
that holds internal state and
produces a new iterator.
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; // the value passed on to the next iteration 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);
fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F> where U: IntoIterator, F: FnMut(Self::Item) -> U
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.
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");
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);
fn inspect<F>(self, f: F) -> Inspect<Self, F> where F: FnMut(&Self::Item) -> ()
Do something with each element of an iterator, passing the value on.
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 much more common for inspect()
to be used as a debugging tool
than to exist in your final code, but never say never.
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);
This will print:
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
fn 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.into_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.into_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);
fn collect<B>(self) -> B where 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);
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]);
Using the 'turbofish' instead of annotationg doubled
:
let a = [1, 2, 3]; let doubled = a.iter() .map(|&x| x * 2) .collect::<Vec<i32>>(); assert_eq!(vec![2, 4, 6], doubled);
Because collect()
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);
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);
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);
fn partition<B, F>(self, f: F) -> (B, B) where B: Default + Extend<Self::Item>, F: FnMut(&Self::Item) -> bool
Consumes an iterator, creating two collections from it.
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.into_iter() .partition(|&n| n % 2 == 0); assert_eq!(even, vec![2]); assert_eq!(odd, vec![1, 3]);
fn fold<B, F>(self, init: B, f: F) -> B where F: FnMut(B, Self::Item) -> B
An iterator adaptor 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. It 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.
Examples
Basic usage:
let a = [1, 2, 3]; // the sum of all of the elements of a let sum = a.iter() .fold(0, |acc, &x| acc + x); assert_eq!(sum, 6);
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);
fn all<F>(&mut self, f: F) -> bool where 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-circuting; 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));
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));
fn any<F>(&mut self, f: F) -> bool where 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-circuting; 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));
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));
fn find<P>(&mut self, predicate: P) -> Option<Self::Item> where P: FnMut(&Self::Item) -> bool
Searches for an element of an iterator that satisfies a predicate.
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-circuting; 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);
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));
fn position<P>(&mut self, predicate: P) -> Option<usize> where P: FnMut(Self::Item) -> bool
Searches for an element in an iterator, returning its index.
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-circuting; 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);
Stopping at the first true
:
let a = [1, 2, 3]; 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));
fn rposition<P>(&mut self, predicate: P) -> Option<usize> where Self: ExactSizeIterator + DoubleEndedIterator, P: FnMut(Self::Item) -> bool
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-circuting; 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);
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));
fn max(self) -> Option<Self::Item> where Self::Item: Ord
Returns the maximum element of an iterator.
If the two elements are equally maximum, the latest element is returned.
Examples
Basic usage:
let a = [1, 2, 3]; assert_eq!(a.iter().max(), Some(&3));
fn min(self) -> Option<Self::Item> where Self::Item: Ord
Returns the minimum element of an iterator.
If the two elements are equally minimum, the first element is returned.
Examples
Basic usage:
let a = [1, 2, 3]; assert_eq!(a.iter().min(), Some(&1));
fn max_by<B, F>(self, f: F) -> Option<Self::Item> where B: Ord, F: FnMut(&Self::Item) -> B
: renamed to max_by_key
fn max_by_key<B, F>(self, f: F) -> Option<Self::Item> where F: FnMut(&Self::Item) -> B, B: Ord
Returns the element that gives the maximum value from the specified function.
Returns the rightmost element if the comparison determines two elements to be equally maximum.
Examples
let a = [-3_i32, 0, 1, 5, -10]; assert_eq!(*a.iter().max_by_key(|x| x.abs()).unwrap(), -10);
fn min_by<B, F>(self, f: F) -> Option<Self::Item> where F: FnMut(&Self::Item) -> B, B: Ord
: renamed to min_by_key
fn min_by_key<B, F>(self, f: F) -> Option<Self::Item> where B: Ord, F: FnMut(&Self::Item) -> B
Returns the element that gives the minimum value from the specified function.
Returns the latest element if the comparison determines two elements to be equally minimum.
Examples
let a = [-3_i32, 0, 1, 5, -10]; assert_eq!(*a.iter().min_by_key(|x| x.abs()).unwrap(), 0);
fn rev(self) -> Rev<Self> where 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);
fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB) where Self: Iterator<Item=(A, B)>, FromA: Default + Extend<A>, FromB: Default + Extend<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]);
fn cloned<'a, T>(self) -> Cloned<Self> where Self: Iterator<Item=&'a T>, T: 'a + Clone
Creates an iterator which clone()s all of its elements.
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]);
fn cycle(self) -> Cycle<Self> where 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));
fn sum<S>(self) -> S where S: Add<Self::Item, Output=S> + Zero
iter_arith
): bounds recently changed
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.
Examples
Basic usage:
#![feature(iter_arith)] let a = [1, 2, 3]; let sum: i32 = a.iter().sum(); assert_eq!(sum, 6);
fn product<P>(self) -> P where P: Mul<Self::Item, Output=P> + One
iter_arith
): bounds recently changed
Iterates over the entire iterator, multiplying all the elements
An empty iterator returns the one value of the type.
Examples
#![feature(iter_arith)] fn factorial(n: u32) -> u32 { (1..).take_while(|&i| i <= n).product() } assert_eq!(factorial(0), 1); assert_eq!(factorial(1), 1); assert_eq!(factorial(5), 120);
fn cmp<I>(self, other: I) -> Ordering where I: IntoIterator<Item=Self::Item>, Self::Item: Ord
Lexicographically compares the elements of this Iterator
with those
of another.
fn partial_cmp<I>(self, other: I) -> Option<Ordering> where I: IntoIterator, Self::Item: PartialOrd<I::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::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::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::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::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::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::Item>
Determines if the elements of this Iterator
are lexicographically
greater than or equal to those of another.
Implementors
impl Iterator for EscapeUnicode
impl Iterator for EscapeDefault
impl<'a, I> Iterator for &'a mut I where I: Iterator + ?Sized
impl<I> Iterator for Rev<I> where I: DoubleEndedIterator
impl<'a, I, T> Iterator for Cloned<I> where T: 'a + Clone, I: Iterator<Item=&'a T>
impl<I> Iterator for Cycle<I> where I: Clone + Iterator
impl<A, B> Iterator for Chain<A, B> where B: Iterator<Item=A::Item>, A: Iterator
impl<A, B> Iterator for Zip<A, B> where B: Iterator, A: Iterator
impl<B, I, F> Iterator for Map<I, F> where I: Iterator, F: FnMut(I::Item) -> B
impl<I, P> Iterator for Filter<I, P> where I: Iterator, P: FnMut(&I::Item) -> bool
impl<B, I, F> Iterator for FilterMap<I, F> where I: Iterator, F: FnMut(I::Item) -> Option<B>
impl<I> Iterator for Enumerate<I> where I: Iterator
impl<I> Iterator for Peekable<I> where I: Iterator
impl<I, P> Iterator for SkipWhile<I, P> where I: Iterator, P: FnMut(&I::Item) -> bool
impl<I, P> Iterator for TakeWhile<I, P> where P: FnMut(&I::Item) -> bool, I: Iterator
impl<I> Iterator for Skip<I> where I: Iterator
impl<I> Iterator for Take<I> where I: Iterator
impl<B, I, St, F> Iterator for Scan<I, St, F> where I: Iterator, F: FnMut(&mut St, I::Item) -> Option<B>
impl<I, U, F> Iterator for FlatMap<I, U, F> where U: IntoIterator, I: Iterator, F: FnMut(I::Item) -> U
impl<I> Iterator for Fuse<I> where I: Iterator
impl<I, F> Iterator for Inspect<I, F> where I: Iterator, F: FnMut(&I::Item) -> ()
impl<A> Iterator for StepBy<A, RangeFrom<A>> where A: Clone, &'a A: Add<&'a A>, &'a A::Output == A
impl<A> Iterator for RangeInclusive<A> where A: PartialEq<A> + Step + One + Clone, &'a A: Add<&'a A>, &'a A::Output == A
impl<A> Iterator for StepBy<A, Range<A>> where A: Zero + Clone + Step
impl<A> Iterator for Range<A> where A: One + Step, &'a A: Add<&'a A>, &'a A::Output == A
impl<A> Iterator for RangeFrom<A> where A: One + Step, &'a A: Add<&'a A>, &'a A::Output == A
impl<A> Iterator for Repeat<A> where A: Clone
impl<T> Iterator for Empty<T>
impl<T> Iterator for Once<T>
impl<A> Iterator for Item<A>
impl<'a, A> Iterator for Iter<'a, A>
impl<'a, A> Iterator for IterMut<'a, A>
impl<A> Iterator for IntoIter<A>
impl<'a, T> Iterator for Iter<'a, T>
impl<'a, T> Iterator for IterMut<'a, T>
impl<T> Iterator for IntoIter<T>
impl<'a, T> Iterator for Iter<'a, T>
impl<'a, T> Iterator for IterMut<'a, T>
impl<'a, T, P> Iterator for Split<'a, T, P> where P: FnMut(&T) -> bool
impl<'a, T, P> Iterator for SplitMut<'a, T, P> where P: FnMut(&T) -> bool
impl<T, I> Iterator for GenericSplitN<I> where I: SplitIter<Item=T>
impl<'a, T, P> Iterator for SplitN<'a, T, P> where P: FnMut(&T) -> bool
impl<'a, T, P> Iterator for RSplitN<'a, T, P> where P: FnMut(&T) -> bool
impl<'a, T, P> Iterator for SplitNMut<'a, T, P> where P: FnMut(&T) -> bool
impl<'a, T, P> Iterator for RSplitNMut<'a, T, P> where P: FnMut(&T) -> bool
impl<'a, T> Iterator for Windows<'a, T>
impl<'a, T> Iterator for Chunks<'a, T>
impl<'a, T> Iterator for ChunksMut<'a, T>
impl<'a> Iterator for Chars<'a>
impl<'a> Iterator for CharIndices<'a>
impl<'a> Iterator for Bytes<'a>
impl<'a, P> Iterator for Split<'a, P> where P: Pattern<'a>
impl<'a, P> Iterator for RSplit<'a, P> where P: Pattern<'a>, P::Searcher: ReverseSearcher<'a>
impl<'a, P> Iterator for SplitTerminator<'a, P> where P: Pattern<'a>
impl<'a, P> Iterator for RSplitTerminator<'a, P> where P: Pattern<'a>, P::Searcher: ReverseSearcher<'a>
impl<'a, P> Iterator for SplitN<'a, P> where P: Pattern<'a>
impl<'a, P> Iterator for RSplitN<'a, P> where P: Pattern<'a>, P::Searcher: ReverseSearcher<'a>
impl<'a, P> Iterator for MatchIndices<'a, P> where P: Pattern<'a>
impl<'a, P> Iterator for RMatchIndices<'a, P> where P: Pattern<'a>, P::Searcher: ReverseSearcher<'a>
impl<'a, P> Iterator for Matches<'a, P> where P: Pattern<'a>
impl<'a, P> Iterator for RMatches<'a, P> where P: Pattern<'a>, P::Searcher: ReverseSearcher<'a>
impl<'a> Iterator for Lines<'a>
impl<'a> Iterator for LinesAny<'a>
impl<I> Iterator for Box<I> where I: Iterator + ?Sized
impl<'a, T> Iterator for Iter<'a, T>
impl<T> Iterator for IntoIter<T>
impl<'a, T> Iterator for Drain<'a, T> where T: 'a
impl<'a, K, V> Iterator for Iter<'a, K, V> where K: 'a, V: 'a
impl<'a, K, V> Iterator for IterMut<'a, K, V> where K: 'a, V: 'a
impl<K, V> Iterator for IntoIter<K, V>
impl<'a, K, V> Iterator for Keys<'a, K, V>
impl<'a, K, V> Iterator for Values<'a, K, V>
impl<'a, K, V> Iterator for Range<'a, K, V>
impl<'a, K, V> Iterator for RangeMut<'a, K, V>
impl<'a, T> Iterator for Iter<'a, T>
impl<T> Iterator for IntoIter<T>
impl<'a, T> Iterator for Range<'a, T>
impl<'a, T> Iterator for Difference<'a, T> where T: Ord
impl<'a, T> Iterator for SymmetricDifference<'a, T> where T: Ord
impl<'a, T> Iterator for Intersection<'a, T> where T: Ord
impl<'a, T> Iterator for Union<'a, T> where T: Ord
impl<E> Iterator for Iter<E> where E: CLike
impl<'a, A> Iterator for Iter<'a, A>
impl<'a, A> Iterator for IterMut<'a, A>
impl<A> Iterator for IntoIter<A>
impl<'a> Iterator for Utf16Units<'a>
impl<'a> Iterator for Drain<'a>
impl<T> Iterator for IntoIter<T>
impl<'a, T> Iterator for Drain<'a, T>
impl<'a, T> Iterator for Iter<'a, T>
impl<'a, T> Iterator for IterMut<'a, T>
impl<T> Iterator for IntoIter<T>
impl<'a, T> Iterator for Drain<'a, T> where T: 'a
impl<I> Iterator for Utf16Encoder<I> where I: Iterator<Item=char>
impl<'a> Iterator for SplitWhitespace<'a>
impl Iterator for ToLowercase
impl Iterator for ToUppercase
impl Iterator for CaseMappingIter
impl<I> Iterator for DecodeUtf16<I> where I: Iterator<Item=u16>
impl<'a, T, R> Iterator for Generator<'a, T, R> where T: Rand, R: Rng
impl<'a, R> Iterator for AsciiGenerator<'a, R> where R: Rng
impl Iterator for EscapeDefault
impl<'a, K, V> Iterator for RawBuckets<'a, K, V>
impl<'a, K, V> Iterator for RevMoveBuckets<'a, K, V>
impl<'a, K, V> Iterator for Iter<'a, K, V>
impl<'a, K, V> Iterator for IterMut<'a, K, V>
impl<K, V> Iterator for IntoIter<K, V>
impl<'a, K, V> Iterator for Drain<'a, K, V>
impl<'a, K, V> Iterator for Iter<'a, K, V>
impl<'a, K, V> Iterator for IterMut<'a, K, V>
impl<K, V> Iterator for IntoIter<K, V>
impl<'a, K, V> Iterator for Keys<'a, K, V>
impl<'a, K, V> Iterator for Values<'a, K, V>
impl<'a, K, V> Iterator for Drain<'a, K, V>
impl<'a, K> Iterator for Iter<'a, K>
impl<K> Iterator for IntoIter<K>
impl<'a, K> Iterator for Drain<'a, K>
impl<'a, T, S> Iterator for Intersection<'a, T, S> where T: Eq + Hash, S: HashState
impl<'a, T, S> Iterator for Difference<'a, T, S> where T: Eq + Hash, S: HashState
impl<'a, T, S> Iterator for SymmetricDifference<'a, T, S> where T: Eq + Hash, S: HashState
impl<'a, T, S> Iterator for Union<'a, T, S> where T: Eq + Hash, S: HashState
impl Iterator for ReadDir