Trait IteratorExtend

pub trait IteratorExtend<A> {
    // Required method
    fn extend<T>(&mut self, iter: T)
       where T: IntoIterator<Item = A>;

    // Provided methods
    fn extend_one(&mut self, item: A) { ... }
    fn extend_reserve(&mut self, additional: usize) { ... }
}

🔄 core Extend a collection with the contents of an iterator.

Re-exported from core::iter:: Extend→IteratorExtend.

---

Extend a collection with the contents of an iterator.

Iterators produce a series of values, and collections can also be thought of as a series of values. The Extend trait bridges this gap, allowing you to extend a collection by including the contents of that iterator. When extending a collection with an already existing key, that entry is updated or, in the case of collections that permit multiple entries with equal keys, that entry is inserted.

Examples

Basic usage:

// You can extend a String with some chars:
let mut message = String::from("The first three letters are: ");

message.extend(&['a', 'b', 'c']);

assert_eq!("abc", &message[29..32]);

Implementing Extend:

// 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);
    }
}

// since MyCollection has a list of i32s, we implement Extend for i32
impl Extend<i32> for MyCollection {

    // This is a bit simpler with the concrete type signature: we can call
    // extend on anything which can be turned into an Iterator which gives
    // us i32s. Because we need i32s to put into MyCollection.
    fn extend<T: IntoIterator<Item=i32>>(&mut self, iter: T) {

        // The implementation is very straightforward: loop through the
        // iterator, and add() each element to ourselves.
        for elem in iter {
            self.add(elem);
        }
    }
}

let mut c = MyCollection::new();

c.add(5);
c.add(6);
c.add(7);

// let's extend our collection with three more numbers
c.extend(vec![1, 2, 3]);

// we've added these elements onto the end
assert_eq!("MyCollection([5, 6, 7, 1, 2, 3])", format!("{c:?}"));

Required Methods

fn extend<T>(&mut self, iter: T)

where T: IntoIterator<Item = A>,

Extends a collection with the contents of an iterator.

As this is the only required method for this trait, the trait-level docs contain more details.

Examples

// You can extend a String with some chars:
let mut message = String::from("abc");

message.extend(['d', 'e', 'f'].iter());

assert_eq!("abcdef", &message);

Provided Methods

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

The default implementation does nothing.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl Extend<AsciiChar> for devela::all::String

impl Extend<char> for devela::all::String

impl Extend<u8> for BytesMut

impl Extend<()> for ()

impl Extend<KeyEventState> for KeyEventState

impl Extend<KeyModifiers> for KeyModifiers

impl Extend<KeyboardEnhancementFlags> for KeyboardEnhancementFlags

impl Extend<Flags> for devela::_dep::ffmpeg_the_third::codec::decoder::slice::Flags

impl Extend<Check> for Check

impl Extend<Conceal> for Conceal

impl Extend<Flags> for devela::_dep::ffmpeg_the_third::codec::packet::Flags

impl Extend<Capabilities> for Capabilities

impl Extend<CodecProperties> for CodecProperties

impl Extend<Debug> for Debug

impl Extend<Flags> for devela::_dep::ffmpeg_the_third::codec::Flags

impl Extend<Flags> for devela::_dep::ffmpeg_the_third::codec::subtitle::Flags

impl Extend<Flags> for devela::_dep::ffmpeg_the_third::filter::Flags

impl Extend<Disposition> for Disposition

impl Extend<Flags> for devela::_dep::ffmpeg_the_third::format::Flags

impl Extend<Flags> for devela::_dep::ffmpeg_the_third::software::resampling::Flags

impl Extend<Flags> for devela::_dep::ffmpeg_the_third::software::scaling::Flags

impl Extend<ChannelLayoutMask> for ChannelLayoutMask

impl Extend<Flags> for devela::_dep::ffmpeg_the_third::util::frame::Flags

impl Extend<Flags> for devela::_dep::ffmpeg_the_third::util::log::Flags

impl Extend<Type> for Type

impl Extend<InitFlag> for devela::_dep::sdl2::image::InitFlag

impl Extend<Mod> for Mod

impl Extend<MessageBoxButtonFlag> for MessageBoxButtonFlag

impl Extend<MessageBoxFlag> for MessageBoxFlag

impl Extend<AllowChangeFlag> for AllowChangeFlag

impl Extend<InitFlag> for devela::_dep::sdl2::mixer::InitFlag

impl Extend<FontStyle> for FontStyle

impl Extend<Channels> for Channels

impl Extend<Table> for ArrayOfTables

impl Extend<OsString> for OsString

impl Extend<String> for devela::all::String

impl Extend<Bytes> for BytesMut

impl Extend<ControlModes> for ControlModes

impl Extend<DupFlags> for DupFlags

impl Extend<EfdFlags> for EfdFlags

impl Extend<EpollCreateFlags> for EpollCreateFlags

impl Extend<EpollFlags> for EpollFlags

impl Extend<EventMask> for EventMask

impl Extend<FdFlags> for FdFlags

impl Extend<Flags> for Flags

impl Extend<InputModes> for InputModes

impl Extend<LocalModes> for LocalModes

impl Extend<OutputModes> for OutputModes

impl Extend<PortCap> for PortCap

impl Extend<PortType> for PortType

impl Extend<ReadWriteFlags> for ReadWriteFlags

impl Extend<Remove> for Remove

impl Extend<Transformations> for Transformations

impl Extend<WatchMask> for WatchMask

impl<'a> Extend<&'a AsciiChar> for devela::all::String

impl<'a> Extend<&'a char> for devela::all::String

impl<'a> Extend<&'a str> for devela::all::String

impl<'a> Extend<&'a u8> for BytesMut

impl<'a> Extend<&'a OsStr> for OsString

impl<'a> Extend<Cow<'a, str>> for devela::all::String

impl<'a> Extend<Cow<'a, OsStr>> for OsString

impl<'a, 'bump> Extend<&'a char> for devela::_dep::bumpalo::collections::String<'bump>

impl<'a, 'bump> Extend<&'a str> for devela::_dep::bumpalo::collections::String<'bump>

impl<'a, 'bump> Extend<Cow<'a, str>> for devela::_dep::bumpalo::collections::String<'bump>

impl<'a, 'bump, T> Extend<&'a T> for devela::_dep::bumpalo::collections::Vec<'bump, T>

where T: 'a + Copy,

Extend implementation that copies elements out of references before pushing them onto the Vec.

This implementation is specialized for slice iterators, where it uses copy_from_slice to append the entire slice at once.

impl<'a, K, V, A> Extend<(&'a K, &'a V)> for BTreeMap<K, V, A>

where K: Ord + Copy, V: Copy, A: Allocator + Clone,

impl<'a, K, V, S> Extend<(&'a K, &'a V)> for devela::_dep::_std::collections::HashMap<K, V, S>

where K: Eq + Hash + Copy, V: Copy, S: BuildHasher,

impl<'a, K, V, S> Extend<(&'a K, &'a V)> for IndexMap<K, V, S>

where K: Hash + Eq + Copy, V: Copy, S: BuildHasher,

impl<'a, K, V, S, A> Extend<&'a (K, V)> for devela::all::HashMap<K, V, S, A>

where K: Eq + Hash + Copy, V: Copy, S: BuildHasher, A: Allocator,

Inserts all new key-values from the iterator and replaces values with existing keys with new values returned from the iterator.

impl<'a, K, V, S, A> Extend<(&'a K, &'a V)> for devela::all::HashMap<K, V, S, A>

where K: Eq + Hash + Copy, V: Copy, S: BuildHasher, A: Allocator,

Inserts all new key-values from the iterator and replaces values with existing keys with new values returned from the iterator.

impl<'a, T, A> Extend<&'a T> for devela::_dep::allocator_api2::vec::Vec<T, A>

where T: Copy + 'a, A: Allocator + 'a,

Extend implementation that copies elements out of references before pushing them onto the Vec.

This implementation is specialized for slice iterators, where it uses copy_from_slice to append the entire slice at once.

impl<'a, T, A> Extend<&'a T> for BTreeSet<T, A>

where T: 'a + Ord + Copy, A: Allocator + Clone,

impl<'a, T, A> Extend<&'a T> for BinaryHeap<T, A>

where T: 'a + Ord + Copy, A: Allocator,

impl<'a, T, A> Extend<&'a T> for LinkedList<T, A>

where T: 'a + Copy, A: Allocator,

impl<'a, T, A> Extend<&'a T> for devela::all::Vec<T, A>

where T: Copy + 'a, A: Allocator,

Extend implementation that copies elements out of references before pushing them onto the Vec.

This implementation is specialized for slice iterators, where it uses copy_from_slice to append the entire slice at once.

impl<'a, T, A> Extend<&'a T> for VecDeque<T, A>

where T: 'a + Copy, A: Allocator,

impl<'a, T, A> Extend<&'a T> for Vec<T, A>

where T: Copy + 'a, A: Allocator + 'a,

Extend implementation that copies elements out of references before pushing them onto the Vec.

This implementation is specialized for slice iterators, where it uses copy_from_slice to append the entire slice at once.

impl<'a, T, S> Extend<&'a T> for devela::_dep::_std::collections::HashSet<T, S>

where T: 'a + Eq + Hash + Copy, S: BuildHasher,

impl<'a, T, S> Extend<&'a T> for IndexSet<T, S>

where T: Hash + Eq + Copy + 'a, S: BuildHasher,

impl<'a, T, S, A> Extend<&'a T> for devela::all::HashSet<T, S, A>

where T: 'a + Eq + Hash + Copy, S: BuildHasher, A: Allocator,

impl<'a, V> Extend<(usize, &'a V)> for VecMap<V>

where V: Copy,

impl<'bump> Extend<char> for devela::_dep::bumpalo::collections::String<'bump>

impl<'bump> Extend<String<'bump>> for devela::_dep::bumpalo::collections::String<'bump>

impl<'bump> Extend<String> for devela::_dep::bumpalo::collections::String<'bump>

impl<'bump, T> Extend<T> for devela::_dep::bumpalo::collections::Vec<'bump, T>

where T: 'bump,

impl<A> Extend<<A as Array>::Item> for SmallVec<A>

where A: Array,

impl<A> Extend<Box<str, A>> for devela::all::String

where A: Allocator,

impl<A> Extend<Box<str, A>> for devela::all::String

where A: Allocator,

impl<A> Extend<Box<str, A>> for devela::all::String

where A: Allocator,

impl<A, EA> Extend<(A₁, A₂, …, Aₙ)> for (EA₁, EA₂, …, EAₙ)

where EA: Extend<A>,

This trait is implemented for tuples up to twelve items long. The impls for 1- and 3- through 12-ary tuples were stabilized after 2-tuples, in 1.85.0.

impl<K, V> Extend<(K, V)> for InlineTable

where K: Into<Key>, V: Into<Value>,

impl<K, V> Extend<(K, V)> for Table

where K: Into<Key>, V: Into<Item>,

impl<K, V, A> Extend<(K, V)> for BTreeMap<K, V, A>

where K: Ord, A: Allocator + Clone,

impl<K, V, S> Extend<(K, V)> for devela::_dep::_std::collections::HashMap<K, V, S>

where K: Eq + Hash, S: BuildHasher,

Inserts all new key-values from the iterator and replaces values with existing keys with new values returned from the iterator.

impl<K, V, S> Extend<(K, V)> for IndexMap<K, V, S>

where K: Hash + Eq, S: BuildHasher,

impl<K, V, S, A> Extend<(K, V)> for devela::all::HashMap<K, V, S, A>

where K: Eq + Hash, S: BuildHasher, A: Allocator,

Inserts all new key-values from the iterator and replaces values with existing keys with new values returned from the iterator.

impl<L, R, A> Extend<A> for Either<L, R>

where L: Extend<A>, R: Extend<A>,

impl<P> Extend<P> for PathBuf

where P: AsRef<Path>,

impl<T> Extend<(Option<HeaderName>, T)> for HeaderMap<T>

impl<T> Extend<(HeaderName, T)> for HeaderMap<T>

impl<T, A> Extend<T> for devela::_dep::allocator_api2::vec::Vec<T, A>

where A: Allocator,

impl<T, A> Extend<T> for BTreeSet<T, A>

where T: Ord, A: Allocator + Clone,

impl<T, A> Extend<T> for BinaryHeap<T, A>

where T: Ord, A: Allocator,

impl<T, A> Extend<T> for LinkedList<T, A>

where A: Allocator,

impl<T, A> Extend<T> for devela::all::Vec<T, A>

where A: Allocator,

impl<T, A> Extend<T> for VecDeque<T, A>

where A: Allocator,

impl<T, A> Extend<T> for Vec<T, A>

where A: Allocator,

impl<T, S> Extend<T> for devela::_dep::_std::collections::HashSet<T, S>

where T: Eq + Hash, S: BuildHasher,

impl<T, S> Extend<T> for IndexSet<T, S>

where T: Hash + Eq, S: BuildHasher,

impl<T, S, A> Extend<T> for devela::all::HashSet<T, S, A>

where T: Eq + Hash, S: BuildHasher, A: Allocator,

impl<T, const CAP: usize> Extend<T> for ArrayVec<T, CAP>

Extend the ArrayVec with an iterator.

Panics if extending the vector exceeds its capacity.

impl<V> Extend<(usize, V)> for VecMap<V>

impl<V> Extend<V> for Array

where V: Into<Value>,