Trait geng::prelude::itertools::__std_iter::FromIterator

pub trait FromIterator<A>: Sized {
    // Required method
    fn from_iter<T>(iter: T) -> Self
       where T: IntoIterator<Item = A>;
}

Conversion from an Iterator.

By implementing FromIterator for a type, you define how it will be created from an iterator. This is common for types which describe a collection of some kind.

If you want to create a collection from the contents of an iterator, the Iterator::collect() method is preferred. However, when you need to specify the container type, FromIterator::from_iter() can be more readable than using a turbofish (e.g. ::<Vec<_>>()). See the Iterator::collect() documentation for more examples of its use.

See also: IntoIterator.

Examples

Basic usage:

let five_fives = std::iter::repeat(5).take(5);

let v = Vec::from_iter(five_fives);

assert_eq!(v, vec![5, 5, 5, 5, 5]);

Using Iterator::collect() to implicitly use FromIterator:

let five_fives = std::iter::repeat(5).take(5);

let v: Vec<i32> = five_fives.collect();

assert_eq!(v, vec![5, 5, 5, 5, 5]);

Using FromIterator::from_iter() as a more readable alternative to Iterator::collect():

use std::collections::VecDeque;
let first = (0..10).collect::<VecDeque<i32>>();
let second = VecDeque::from_iter(0..10);

assert_eq!(first, second);

Implementing FromIterator 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 FromIterator
impl FromIterator<i32> for MyCollection {
    fn from_iter<I: IntoIterator<Item=i32>>(iter: I) -> Self {
        let mut c = MyCollection::new();

        for i in iter {
            c.add(i);
        }

        c
    }
}

// Now we can make a new iterator...
let iter = (0..5).into_iter();

// ... and make a MyCollection out of it
let c = MyCollection::from_iter(iter);

assert_eq!(c.0, vec![0, 1, 2, 3, 4]);

// collect works too!

let iter = (0..5).into_iter();
let c: MyCollection = iter.collect();

assert_eq!(c.0, vec![0, 1, 2, 3, 4]);

Required Methods

fn from_iter<T>(iter: T) -> Self

where T: IntoIterator<Item = A>,

Creates a value from an iterator.

See the module-level documentation for more.

Examples

let five_fives = std::iter::repeat(5).take(5);

let v = Vec::from_iter(five_fives);

assert_eq!(v, vec![5, 5, 5, 5, 5]);

Object Safety

This trait is not object safe.

Implementors

impl FromIterator<(Value, Value)> for geng::prelude::ron::Map

impl FromIterator<(String, Value)> for geng::prelude::serde_json::Map<String, Value>

impl FromIterator<(String, Value)> for geng::prelude::toml::map::Map<String, Value>

impl FromIterator<char> for String

impl FromIterator<char> for SmolStr

impl FromIterator<u8> for bytes::bytes::Bytes

impl FromIterator<u8> for bytes::bytes::BytesMut

impl FromIterator<u8> for Bytes

impl FromIterator<u8> for BytesMut

impl FromIterator<()> for ()

Collapses all unit items from an iterator into one.

This is more useful when combined with higher-level abstractions, like collecting to a Result<(), E> where you only care about errors:

use std::io::*;
let data = vec![1, 2, 3, 4, 5];
let res: Result<()> = data.iter()
    .map(|x| writeln!(stdout(), "{x}"))
    .collect();
assert!(res.is_ok());

impl FromIterator<Extensions> for Extensions

impl FromIterator<Box<str>> for String

impl FromIterator<String> for String

impl FromIterator<String> for SmolStr

impl FromIterator<OsString> for OsString

impl FromIterator<Access> for Access

impl FromIterator<Access> for Access

impl FromIterator<AccessFlags> for AccessFlags

impl FromIterator<Anchor> for Anchor

impl FromIterator<Anchor> for Anchor

impl FromIterator<Api> for Api

impl FromIterator<AtFlags> for AtFlags

impl FromIterator<AtFlags> for AtFlags

impl FromIterator<AtFlags> for AtFlags

impl FromIterator<CapabilitiesSecureBits> for CapabilitiesSecureBits

impl FromIterator<Capability> for Capability

impl FromIterator<Capability> for Capability

impl FromIterator<Capability> for Capability

impl FromIterator<CapabilityFlags> for CapabilityFlags

impl FromIterator<Channels> for Channels

impl FromIterator<ConfigSurfaceTypes> for ConfigSurfaceTypes

impl FromIterator<ConstraintAdjustment> for ConstraintAdjustment

impl FromIterator<ContentHint> for ContentHint

impl FromIterator<ContentHint> for ContentHint

impl FromIterator<ContentHint> for ContentHint

impl FromIterator<ControlModes> for ControlModes

impl FromIterator<CreateFlags> for CreateFlags

impl FromIterator<CreateFlags> for CreateFlags

impl FromIterator<CreateFlags> for CreateFlags

impl FromIterator<CreateFlags> for CreateFlags

impl FromIterator<DisplayFeatures> for DisplayFeatures

impl FromIterator<DndAction> for DndAction

impl FromIterator<DupFlags> for DupFlags

impl FromIterator<DupFlags> for DupFlags

impl FromIterator<EfdFlags> for EfdFlags

impl FromIterator<EfdFlags> for EfdFlags

impl FromIterator<EpollCreateFlags> for EpollCreateFlags

impl FromIterator<EpollCreateFlags> for EpollCreateFlags

impl FromIterator<EpollFlags> for EpollFlags

impl FromIterator<EpollFlags> for EpollFlags

impl FromIterator<EventFlags> for EventFlags

impl FromIterator<EventFlags> for EventFlags

impl FromIterator<EventMask> for EventMask

impl FromIterator<EventMask> for EventMask

impl FromIterator<EventfdFlags> for EventfdFlags

impl FromIterator<EventfdFlags> for EventfdFlags

impl FromIterator<FallocateFlags> for FallocateFlags

impl FromIterator<FallocateFlags> for FallocateFlags

impl FromIterator<FallocateFlags> for FallocateFlags

impl FromIterator<FdFlag> for FdFlag

impl FromIterator<FdFlags> for FdFlags

impl FromIterator<FdFlags> for FdFlags

impl FromIterator<Flags> for Flags

impl FromIterator<Flags> for Flags

impl FromIterator<Flags> for Flags

impl FromIterator<FloatingPointEmulationControl> for FloatingPointEmulationControl

impl FromIterator<FloatingPointExceptionMode> for FloatingPointExceptionMode

impl FromIterator<FsFlags> for FsFlags

impl FromIterator<FutexFlags> for FutexFlags

impl FromIterator<InputModes> for InputModes

impl FromIterator<Kind> for Kind

impl FromIterator<Literal> for Seq

impl FromIterator<LocalModes> for LocalModes

impl FromIterator<MRemapFlags> for MRemapFlags

impl FromIterator<MapFlags> for MapFlags

impl FromIterator<MemFdCreateFlag> for MemFdCreateFlag

impl FromIterator<MembarrierQuery> for MembarrierQuery

impl FromIterator<MemfdFlags> for MemfdFlags

impl FromIterator<MemfdFlags> for MemfdFlags

impl FromIterator<MlockAllFlags> for MlockAllFlags

impl FromIterator<Mode> for Mode

impl FromIterator<Mode> for Mode

impl FromIterator<Mode> for Mode

impl FromIterator<Mode> for Mode

impl FromIterator<ModifiersState> for ModifiersState

impl FromIterator<MountFlags> for MountFlags

impl FromIterator<MountFlags> for MountFlags

impl FromIterator<MountPropagationFlags> for MountPropagationFlags

impl FromIterator<MountPropagationFlags> for MountPropagationFlags

impl FromIterator<MsFlags> for MsFlags

impl FromIterator<MsgFlags> for MsgFlags

impl FromIterator<OFlag> for OFlag

impl FromIterator<OFlags> for OFlags

impl FromIterator<OFlags> for OFlags

impl FromIterator<OutputModes> for OutputModes

impl FromIterator<PidfdFlags> for PidfdFlags

impl FromIterator<PidfdGetfdFlags> for PidfdGetfdFlags

impl FromIterator<PipeFlags> for PipeFlags

impl FromIterator<PipeFlags> for PipeFlags

impl FromIterator<PollFlags> for PollFlags

impl FromIterator<PollFlags> for PollFlags

impl FromIterator<PollFlags> for PollFlags

impl FromIterator<PortCap> for PortCap

impl FromIterator<PortType> for PortType

impl FromIterator<ProtFlags> for ProtFlags

impl FromIterator<ReadWriteFlags> for ReadWriteFlags

impl FromIterator<ReadWriteFlags> for ReadWriteFlags

impl FromIterator<RecvFlags> for RecvFlags

impl FromIterator<Remove> for Remove

impl FromIterator<RenameFlags> for RenameFlags

impl FromIterator<RenameFlags> for RenameFlags

impl FromIterator<RenameFlags> for RenameFlags

impl FromIterator<Resize> for Resize

impl FromIterator<ResolveFlags> for ResolveFlags

impl FromIterator<ResolveFlags> for ResolveFlags

impl FromIterator<SFlag> for SFlag

impl FromIterator<SealFlag> for SealFlag

impl FromIterator<SealFlags> for SealFlags

impl FromIterator<SealFlags> for SealFlags

impl FromIterator<SendFlags> for SendFlags

impl FromIterator<ShmOFlags> for ShmOFlags

impl FromIterator<SockFlag> for SockFlag

impl FromIterator<SocketFlags> for SocketFlags

impl FromIterator<SpeculationFeatureControl> for SpeculationFeatureControl

impl FromIterator<SpeculationFeatureState> for SpeculationFeatureState

impl FromIterator<SpliceFlags> for SpliceFlags

impl FromIterator<SpliceFlags> for SpliceFlags

impl FromIterator<StatVfsMountFlags> for StatVfsMountFlags

impl FromIterator<StatVfsMountFlags> for StatVfsMountFlags

impl FromIterator<StatxFlags> for StatxFlags

impl FromIterator<StatxFlags> for StatxFlags

impl FromIterator<Table> for ArrayOfTables

impl FromIterator<TaggedAddressMode> for TaggedAddressMode

impl FromIterator<ThreadNameSpaceType> for ThreadNameSpaceType

impl FromIterator<TimerfdFlags> for TimerfdFlags

impl FromIterator<TimerfdTimerFlags> for TimerfdTimerFlags

impl FromIterator<TimestampingFlag> for TimestampingFlag

impl FromIterator<TrancheFlags> for TrancheFlags

impl FromIterator<Transformations> for Transformations

impl FromIterator<Transient> for Transient

impl FromIterator<UnalignedAccessControl> for UnalignedAccessControl

impl FromIterator<UnmountFlags> for UnmountFlags

impl FromIterator<UnmountFlags> for UnmountFlags

impl FromIterator<UnshareFlags> for UnshareFlags

impl FromIterator<WaitOptions> for WaitOptions

impl FromIterator<WaitidOptions> for WaitidOptions

impl FromIterator<WatchFlags> for WatchFlags

impl FromIterator<WatchFlags> for WatchFlags

impl FromIterator<WatchMask> for WatchMask

impl FromIterator<WatchMask> for WatchMask

impl FromIterator<WindowButtons> for WindowButtons

impl FromIterator<WindowManagerCapabilities> for WindowManagerCapabilities

impl FromIterator<WindowState> for WindowState

impl FromIterator<XattrFlags> for XattrFlags

impl FromIterator<XattrFlags> for XattrFlags

impl FromIterator<xkb_state_component> for xkb_state_component

impl<'a> FromIterator<&'a char> for String

impl<'a> FromIterator<&'a str> for String

impl<'a> FromIterator<&'a str> for SmolStr

impl<'a> FromIterator<&'a u8> for bytes::bytes::Bytes

impl<'a> FromIterator<&'a u8> for bytes::bytes::BytesMut

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

impl<'a> FromIterator<&'a String> for SmolStr

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

impl<'a> FromIterator<Cow<'a, str>> for String

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

impl<'a> FromIterator<char> for Cow<'a, str>

impl<'a> FromIterator<String> for Cow<'a, str>

impl<'a, 'b> FromIterator<&'b str> for Cow<'a, str>

impl<'a, T> FromIterator<T> for Cow<'a, [T]>

where T: Clone,

impl<A> FromIterator<<A as Array>::Item> for ArrayVec<A>

where A: Array,

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

where A: Array,

impl<A> FromIterator<<A as Array>::Item> for TinyVec<A>

where A: Array,

impl<A, E, V> FromIterator<Result<A, E>> for Result<V, E>

where V: FromIterator<A>,

impl<A, V> FromIterator<Option<A>> for Option<V>

where V: FromIterator<A>,

impl<F> FromIterator<F> for JoinAll<F>

where F: Future,

impl<F> FromIterator<F> for TryJoinAll<F>

where F: TryFuture,

impl<Fut> FromIterator<Fut> for geng::prelude::futures::prelude::future::SelectAll<Fut>

where Fut: Future + Unpin,

impl<Fut> FromIterator<Fut> for SelectOk<Fut>

where Fut: TryFuture + Unpin,

impl<Fut> FromIterator<Fut> for FuturesOrdered<Fut>

where Fut: Future,

impl<Fut> FromIterator<Fut> for FuturesUnordered<Fut>

impl<I> FromIterator<I> for Box<[I]>

impl<K, V> FromIterator<(K, V)> for geng::prelude::serde_json::Value

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

impl<K, V> FromIterator<(K, V)> for BTreeMap<K, V>

where K: Ord,

impl<K, V> FromIterator<(K, V)> for AHashMap<K, V>

where K: Eq + Hash,

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

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

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

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

impl<K, V> FromIterator<(K, V)> for Value

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

impl<K, V, S> FromIterator<(K, V)> for geng::prelude::HashMap<K, V, S>

where K: Eq + Hash, S: BuildHasher + Default,

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

where K: Hash + Eq, S: BuildHasher + Default,

impl<K, V, S, A> FromIterator<(K, V)> for HashMap<K, V, S, A>

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

impl<P> FromIterator<P> for std::path::PathBuf

where P: AsRef<Path>,

impl<P> FromIterator<P> for PathBuf

where P: AsRef<Path>,

impl<St> FromIterator<St> for geng::prelude::futures::prelude::stream::SelectAll<St>

where St: Stream + Unpin,

impl<T> FromIterator<(usize, T)> for Slab<T>

Create a slab from an iterator of key-value pairs.

If the iterator produces duplicate keys, the previous value is replaced with the later one. The keys does not need to be sorted beforehand, and this function always takes O(n) time. Note that the returned slab will use space proportional to the largest key, so don’t use Slab with untrusted keys.

Examples

let vec = vec![(2,'a'), (6,'b'), (7,'c')];
let slab = vec.into_iter().collect::<Slab<char>>();
assert_eq!(slab.len(), 3);
assert!(slab.capacity() >= 8);
assert_eq!(slab[2], 'a');

With duplicate and unsorted keys:

let vec = vec![(20,'a'), (10,'b'), (11,'c'), (10,'d')];
let slab = vec.into_iter().collect::<Slab<char>>();
assert_eq!(slab.len(), 3);
assert_eq!(slab[10], 'd');

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

impl<T> FromIterator<Steal<T>> for Steal<T>

impl<T> FromIterator<T> for geng::prelude::serde_json::Value

where T: Into<Value>,

impl<T> FromIterator<T> for Arc<[T]>

impl<T> FromIterator<T> for Collection<T>

where T: HasId,

impl<T> FromIterator<T> for Rc<[T]>

impl<T> FromIterator<T> for BinaryHeap<T>

where T: Ord,

impl<T> FromIterator<T> for BTreeSet<T>

where T: Ord,

impl<T> FromIterator<T> for LinkedList<T>

impl<T> FromIterator<T> for VecDeque<T>

impl<T> FromIterator<T> for Vec<T>

impl<T> FromIterator<T> for AHashSet<T>

where T: Eq + Hash,

impl<T, N> FromIterator<T> for GenericArray<T, N>

where N: ArrayLength<T>,

impl<T, S> FromIterator<T> for geng::prelude::HashSet<T, S>

where T: Eq + Hash, S: BuildHasher + Default,

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

where T: Hash + Eq, S: BuildHasher + Default,

impl<T, S, A> FromIterator<T> for HashSet<T, S, A>

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

impl<T, const CAP: usize> FromIterator<T> for arrayvec::arrayvec::ArrayVec<T, CAP>

Create an ArrayVec from an iterator.

Panics if the number of elements in the iterator exceeds the arrayvec’s capacity.

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

impl<V> FromIterator<V> for Array

where V: Into<Value>,

impl<V> FromIterator<V> for Value

where V: Into<Value>,