1.0.0[−][src]Trait cron_clock::lib::std::iter::IntoIterator
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 = vec![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
type Item
The type of the elements being iterated over.
type IntoIter: Iterator
Which kind of iterator are we turning this into?
Required methods
fn into_iter(self) -> Self::IntoIter
Creates an iterator from a value.
See the module-level documentation for more.
Examples
Basic usage:
let v = vec![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
impl<'a> IntoIterator for &'a Path
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impl<'a> IntoIterator for &'a UnixListener
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type Item = Result<UnixStream, Error>
type IntoIter = Incoming<'a>
fn into_iter(self) -> Incoming<'a>
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impl<'a, T> IntoIterator for &'a Receiver<T>
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impl<'a> IntoIterator for &'a PathBuf
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impl<T> IntoIterator for Receiver<T>
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impl<'a, T> IntoIterator for &'a mut [T]
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impl<'a, const N: usize, T> IntoIterator for &'a mut [T; N] where
[T; N]: LengthAtMost32,
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[T; N]: LengthAtMost32,
impl<'a, T> IntoIterator for &'a [T]
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impl<'a, const N: usize, T> IntoIterator for &'a [T; N] where
[T; N]: LengthAtMost32,
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[T; N]: LengthAtMost32,
impl<'a, K, V, S> IntoIterator for &'a HashMap<K, V, S>
impl<T, S> IntoIterator for HashSet<T, S>
type Item = T
type IntoIter = IntoIter<T>
fn into_iter(self) -> IntoIter<T>
Creates a consuming iterator, that is, one that moves each value out of the set in arbitrary order. The set cannot be used after calling this.
Examples
use hashbrown::HashSet; let mut set = HashSet::new(); set.insert("a".to_string()); set.insert("b".to_string()); // Not possible to collect to a Vec<String> with a regular `.iter()`. let v: Vec<String> = set.into_iter().collect(); // Will print in an arbitrary order. for x in &v { println!("{}", x); }
impl<'a, K, V, S> IntoIterator for &'a mut HashMap<K, V, S>
type Item = (&'a K, &'a mut V)
type IntoIter = IterMut<'a, K, V>
fn into_iter(self) -> IterMut<'a, K, V>
impl<K, V, S> IntoIterator for HashMap<K, V, S>
type Item = (K, V)
type IntoIter = IntoIter<K, V>
fn into_iter(self) -> IntoIter<K, V>
Creates a consuming iterator, that is, one that moves each key-value pair out of the map in arbitrary order. The map cannot be used after calling this.
Examples
use hashbrown::HashMap; let mut map = HashMap::new(); map.insert("a", 1); map.insert("b", 2); map.insert("c", 3); // Not possible with .iter() let vec: Vec<(&str, i32)> = map.into_iter().collect();
impl<'a, T, S> IntoIterator for &'a HashSet<T, S>
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Implementors
impl<'a, K, V> IntoIterator for &'a BTreeMap<K, V> where
K: 'a,
V: 'a,
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K: 'a,
V: 'a,
impl<'a, K, V> IntoIterator for &'a mut BTreeMap<K, V> where
K: 'a,
V: 'a,
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K: 'a,
V: 'a,
type Item = (&'a K, &'a mut V)
type IntoIter = IterMut<'a, K, V>
fn into_iter(self) -> IterMut<'a, K, V>
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impl<'a, K, V, S> IntoIterator for &'a cron_clock::lib::std::collections::HashMap<K, V, S>
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impl<'a, K, V, S> IntoIterator for &'a mut cron_clock::lib::std::collections::HashMap<K, V, S>
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type Item = (&'a K, &'a mut V)
type IntoIter = IterMut<'a, K, V>
fn into_iter(self) -> IterMut<'a, K, V>
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impl<'a, T> IntoIterator for &'a Option<T>
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impl<'a, T> IntoIterator for &'a BTreeSet<T>
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impl<'a, T> IntoIterator for &'a BinaryHeap<T>
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impl<'a, T> IntoIterator for &'a LinkedList<T>
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impl<'a, T> IntoIterator for &'a VecDeque<T>
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impl<'a, T> IntoIterator for &'a Vec<T>
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impl<'a, T> IntoIterator for &'a mut Option<T>
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impl<'a, T> IntoIterator for &'a mut LinkedList<T>
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impl<'a, T> IntoIterator for &'a mut VecDeque<T>
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impl<'a, T> IntoIterator for &'a mut Vec<T>
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impl<'a, T, E> IntoIterator for &'a Result<T, E>
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impl<'a, T, E> IntoIterator for &'a mut Result<T, E>
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impl<'a, T, S> IntoIterator for &'a cron_clock::lib::std::collections::HashSet<T, S>
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impl<I> IntoIterator for I where
I: Iterator,
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I: Iterator,
impl<K, V> IntoIterator for BTreeMap<K, V>
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impl<K, V, S> IntoIterator for cron_clock::lib::std::collections::HashMap<K, V, S>
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type Item = (K, V)
type IntoIter = IntoIter<K, V>
fn into_iter(self) -> IntoIter<K, V>
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Creates a consuming iterator, that is, one that moves each key-value pair out of the map in arbitrary order. The map cannot be used after calling this.
Examples
use std::collections::HashMap; let mut map = HashMap::new(); map.insert("a", 1); map.insert("b", 2); map.insert("c", 3); // Not possible with .iter() let vec: Vec<(&str, i32)> = map.into_iter().collect();
impl<T> IntoIterator for Option<T>
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type Item = T
type IntoIter = IntoIter<T>
fn into_iter(self) -> IntoIter<T>
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Returns a consuming iterator over the possibly contained value.
Examples
let x = Some("string"); let v: Vec<&str> = x.into_iter().collect(); assert_eq!(v, ["string"]); let x = None; let v: Vec<&str> = x.into_iter().collect(); assert!(v.is_empty());
impl<T> IntoIterator for BTreeSet<T>
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type Item = T
type IntoIter = IntoIter<T>
fn into_iter(self) -> IntoIter<T>
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Gets an iterator for moving out the BTreeSet
's contents.
Examples
use std::collections::BTreeSet; let set: BTreeSet<usize> = [1, 2, 3, 4].iter().cloned().collect(); let v: Vec<_> = set.into_iter().collect(); assert_eq!(v, [1, 2, 3, 4]);
impl<T> IntoIterator for BinaryHeap<T>
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type Item = T
type IntoIter = IntoIter<T>
fn into_iter(self) -> IntoIter<T>
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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(vec![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); }
impl<T> IntoIterator for LinkedList<T>
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type Item = T
type IntoIter = IntoIter<T>
fn into_iter(self) -> IntoIter<T>
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Consumes the list into an iterator yielding elements by value.
impl<T> IntoIterator for VecDeque<T>
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type Item = T
type IntoIter = IntoIter<T>
fn into_iter(self) -> IntoIter<T>
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Consumes the VecDeque
into a front-to-back iterator yielding elements by
value.
impl<T> IntoIterator for Vec<T>
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type Item = T
type IntoIter = IntoIter<T>
fn into_iter(self) -> IntoIter<T>
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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); }
impl<T, E> IntoIterator for Result<T, E>
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type Item = T
type IntoIter = IntoIter<T>
fn into_iter(self) -> IntoIter<T>
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Returns a consuming iterator over the possibly contained value.
The iterator yields one value if the result is Result::Ok
, otherwise none.
Examples
Basic usage:
let x: Result<u32, &str> = Ok(5); let v: Vec<u32> = x.into_iter().collect(); assert_eq!(v, [5]); let x: Result<u32, &str> = Err("nothing!"); let v: Vec<u32> = x.into_iter().collect(); assert_eq!(v, []);
impl<T, S> IntoIterator for cron_clock::lib::std::collections::HashSet<T, S>
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type Item = T
type IntoIter = IntoIter<T>
fn into_iter(self) -> IntoIter<T>
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Creates a consuming iterator, that is, one that moves each value out of the set in arbitrary order. The set cannot be used after calling this.
Examples
use std::collections::HashSet; let mut set = HashSet::new(); set.insert("a".to_string()); set.insert("b".to_string()); // Not possible to collect to a Vec<String> with a regular `.iter()`. let v: Vec<String> = set.into_iter().collect(); // Will print in an arbitrary order. for x in &v { println!("{}", x); }