Trait signature_core::lib::iter::IntoIterator
1.0.0 · source · [−]pub trait IntoIterator {
type Item;
type IntoIter: Iterator;
fn into_iter(self) -> Self::IntoIter;
}
Expand description
Conversion into an Iterator
.
By implementing IntoIterator
for a type, you define how it will be
converted to an iterator. This is common for types which describe a
collection of some kind.
One benefit of implementing IntoIterator
is that your type will work
with Rust’s for
loop syntax.
See also: FromIterator
.
Examples
Basic usage:
let v = [1, 2, 3];
let mut iter = v.into_iter();
assert_eq!(Some(1), iter.next());
assert_eq!(Some(2), iter.next());
assert_eq!(Some(3), iter.next());
assert_eq!(None, iter.next());
Implementing IntoIterator
for your type:
// A sample collection, that's just a wrapper over Vec<T>
#[derive(Debug)]
struct MyCollection(Vec<i32>);
// Let's give it some methods so we can create one and add things
// to it.
impl MyCollection {
fn new() -> MyCollection {
MyCollection(Vec::new())
}
fn add(&mut self, elem: i32) {
self.0.push(elem);
}
}
// and we'll implement IntoIterator
impl IntoIterator for MyCollection {
type Item = i32;
type IntoIter = std::vec::IntoIter<Self::Item>;
fn into_iter(self) -> Self::IntoIter {
self.0.into_iter()
}
}
// Now we can make a new collection...
let mut c = MyCollection::new();
// ... add some stuff to it ...
c.add(0);
c.add(1);
c.add(2);
// ... and then turn it into an Iterator:
for (i, n) in c.into_iter().enumerate() {
assert_eq!(i as i32, n);
}
It is common to use IntoIterator
as a trait bound. This allows
the input collection type to change, so long as it is still an
iterator. Additional bounds can be specified by restricting on
Item
:
fn collect_as_strings<T>(collection: T) -> Vec<String>
where
T: IntoIterator,
T::Item: std::fmt::Debug,
{
collection
.into_iter()
.map(|item| format!("{:?}", item))
.collect()
}
Associated Types
Required methods
Creates an iterator from a value.
See the module-level documentation for more.
Examples
Basic usage:
let v = [1, 2, 3];
let mut iter = v.into_iter();
assert_eq!(Some(1), iter.next());
assert_eq!(Some(2), iter.next());
assert_eq!(Some(3), iter.next());
assert_eq!(None, iter.next());
Implementations on Foreign Types
Creates a consuming iterator, that is, one that moves each value out of
the array (from start to end). The array cannot be used after calling
this unless T
implements Copy
, so the whole array is copied.
Arrays have special behavior when calling .into_iter()
prior to the
2021 edition – see the array Editions section for more information.
type Item = T
impl<'a, T, N> IntoIterator for &'a GenericArray<T, N> where
T: 'a,
N: ArrayLength<T>,
impl<'a, T, N> IntoIterator for &'a GenericArray<T, N> where
T: 'a,
N: ArrayLength<T>,
impl<T, N> IntoIterator for GenericArray<T, N> where
N: ArrayLength<T>,
impl<T, N> IntoIterator for GenericArray<T, N> where
N: ArrayLength<T>,
type Item = T
type IntoIter = GenericArrayIter<T, N>
pub fn into_iter(self) -> <GenericArray<T, N> as IntoIterator>::IntoIter
impl<'a, T, N> IntoIterator for &'a mut GenericArray<T, N> where
T: 'a,
N: ArrayLength<T>,
impl<'a, T, N> IntoIterator for &'a mut GenericArray<T, N> where
T: 'a,
N: ArrayLength<T>,
Creates a consuming iterator, that is, one that moves each value out of the binary heap in arbitrary order. The binary heap cannot be used after calling this.
Examples
Basic usage:
use std::collections::BinaryHeap;
let heap = BinaryHeap::from([1, 2, 3, 4]);
// Print 1, 2, 3, 4 in arbitrary order
for x in heap.into_iter() {
// x has type i32, not &i32
println!("{}", x);
}
type Item = T
Creates a consuming iterator, that is, one that moves each value out of the vector (from start to end). The vector cannot be used after calling this.
Examples
let v = vec!["a".to_string(), "b".to_string()];
for s in v.into_iter() {
// s has type String, not &String
println!("{}", s);
}