Trait Extend

pub trait Extend<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) { ... }
}

Available on crate feature std only.

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<char> for devela::all::String

impl Extend<u8> for BytesMut

impl Extend<()> for ()

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

impl Extend<OsString> for OsString

impl Extend<KeyEventState> for KeyEventState

impl Extend<KeyModifiers> for KeyModifiers

impl Extend<KeyboardEnhancementFlags> for KeyboardEnhancementFlags

impl Extend<CreateFlags> for devela::_dep::rustix::event::epoll::CreateFlags

impl Extend<EventfdFlags> for EventfdFlags

impl Extend<PollFlags> for PollFlags

impl Extend<CreateFlags> for devela::_dep::rustix::fs::inotify::CreateFlags

impl Extend<ReadFlags> for ReadFlags

impl Extend<WatchFlags> for WatchFlags

impl Extend<Access> for Access

impl Extend<AtFlags> for AtFlags

impl Extend<FallocateFlags> for FallocateFlags

impl Extend<FdFlags> for FdFlags

impl Extend<IFlags> for IFlags

impl Extend<MemfdFlags> for MemfdFlags

impl Extend<Mode> for Mode

impl Extend<MountFlags> for MountFlags

impl Extend<MountPropagationFlags> for MountPropagationFlags

impl Extend<OFlags> for OFlags

impl Extend<RenameFlags> for RenameFlags

impl Extend<ResolveFlags> for ResolveFlags

impl Extend<SealFlags> for SealFlags

impl Extend<StatVfsMountFlags> for StatVfsMountFlags

impl Extend<StatxFlags> for StatxFlags

impl Extend<UnmountFlags> for UnmountFlags

impl Extend<XattrFlags> for XattrFlags

impl Extend<DupFlags> for DupFlags

impl Extend<ReadWriteFlags> for ReadWriteFlags

impl Extend<EventFlags> for EventFlags

impl Extend<IoringAcceptFlags> for IoringAcceptFlags

impl Extend<IoringAsyncCancelFlags> for IoringAsyncCancelFlags

impl Extend<IoringCqFlags> for IoringCqFlags

impl Extend<IoringCqeFlags> for IoringCqeFlags

impl Extend<IoringEnterFlags> for IoringEnterFlags

impl Extend<IoringFeatureFlags> for IoringFeatureFlags

impl Extend<IoringFsyncFlags> for IoringFsyncFlags

impl Extend<IoringMsgringFlags> for IoringMsgringFlags

impl Extend<IoringOpFlags> for IoringOpFlags

impl Extend<IoringPollFlags> for IoringPollFlags

impl Extend<IoringRecvFlags> for IoringRecvFlags

impl Extend<IoringRegisterFlags> for IoringRegisterFlags

impl Extend<IoringRsrcFlags> for IoringRsrcFlags

impl Extend<IoringSendFlags> for IoringSendFlags

impl Extend<IoringSetupFlags> for IoringSetupFlags

impl Extend<IoringSqFlags> for IoringSqFlags

impl Extend<IoringSqeFlags> for IoringSqeFlags

impl Extend<IoringTimeoutFlags> for IoringTimeoutFlags

impl Extend<RecvFlags> for RecvFlags

impl Extend<RecvmsgOutFlags> for RecvmsgOutFlags

impl Extend<SendFlags> for SendFlags

impl Extend<SocketFlags> for SocketFlags

impl Extend<SpliceFlags> for devela::_dep::rustix::io_uring::SpliceFlags

impl Extend<MapFlags> for MapFlags

impl Extend<MlockAllFlags> for MlockAllFlags

impl Extend<MlockFlags> for MlockFlags

impl Extend<MprotectFlags> for MprotectFlags

impl Extend<MremapFlags> for MremapFlags

impl Extend<MsyncFlags> for MsyncFlags

impl Extend<ProtFlags> for ProtFlags

impl Extend<UserfaultfdFlags> for UserfaultfdFlags

impl Extend<FsMountFlags> for FsMountFlags

impl Extend<FsOpenFlags> for FsOpenFlags

impl Extend<FsPickFlags> for FsPickFlags

impl Extend<MountAttrFlags> for MountAttrFlags

impl Extend<MoveMountFlags> for MoveMountFlags

impl Extend<OpenTreeFlags> for OpenTreeFlags

impl Extend<SockaddrXdpFlags> for SockaddrXdpFlags

impl Extend<XdpDescOptions> for XdpDescOptions

impl Extend<XdpOptionsFlags> for XdpOptionsFlags

impl Extend<XdpRingFlags> for XdpRingFlags

impl Extend<XdpUmemRegFlags> for XdpUmemRegFlags

impl Extend<PipeFlags> for PipeFlags

impl Extend<SpliceFlags> for devela::_dep::rustix::pipe::SpliceFlags

impl Extend<FloatingPointEmulationControl> for FloatingPointEmulationControl

impl Extend<FloatingPointExceptionMode> for FloatingPointExceptionMode

impl Extend<MembarrierQuery> for MembarrierQuery

impl Extend<PidfdFlags> for PidfdFlags

impl Extend<PidfdGetfdFlags> for PidfdGetfdFlags

impl Extend<SpeculationFeatureControl> for SpeculationFeatureControl

impl Extend<SpeculationFeatureState> for SpeculationFeatureState

impl Extend<UnalignedAccessControl> for UnalignedAccessControl

impl Extend<WaitOptions> for WaitOptions

impl Extend<WaitidOptions> for WaitidOptions

impl Extend<OpenptFlags> for OpenptFlags

impl Extend<GetRandomFlags> for GetRandomFlags

impl Extend<ShmOFlags> for ShmOFlags

impl Extend<ControlModes> for ControlModes

impl Extend<InputModes> for InputModes

impl Extend<LocalModes> for LocalModes

impl Extend<OutputModes> for OutputModes

impl Extend<CapabilitiesSecureBits> for CapabilitiesSecureBits

impl Extend<CapabilityFlags> for CapabilityFlags

impl Extend<Flags> for devela::_dep::rustix::thread::FutexFlags

impl Extend<TaggedAddressMode> for TaggedAddressMode

impl Extend<ThreadNameSpaceType> for ThreadNameSpaceType

impl Extend<UnshareFlags> for UnshareFlags

impl Extend<TimerfdFlags> for TimerfdFlags

impl Extend<TimerfdTimerFlags> for TimerfdTimerFlags

impl Extend<Channels> for Channels

impl Extend<Bytes> for BytesMut

impl Extend<Flags> for Flags

impl Extend<PortCap> for PortCap

impl Extend<PortType> for PortType

impl Extend<Remove> for Remove

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

where T: 'a + Eq + Hash + Copy, 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<'bump> Extend<char> for devela::_dep::bumpalo::collections::String<'bump>

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

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

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

where T: 'bump,

impl<'slice, 'fd> Extend<SendAncillaryMessage<'slice, 'fd>> for SendAncillaryBuffer<'_, 'slice, 'fd>

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<A> for Array

where A: AsRef<JsValue>,

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

where T: Eq + Hash, 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.