Trait artifact_app::dev_prefix::FromIterator

pub trait FromIterator<A> {
    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.

FromIterator's from_iter is rarely called explicitly, and is instead used through Iterator's collect method. See collect's documentation for more examples.

See also: IntoIterator.

Examples

Basic usage:

use std::iter::FromIterator;

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 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]);

Implementing FromIterator for your type:

use std::iter::FromIterator;

// 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

Basic usage:

use std::iter::FromIterator;

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]);

Implementations on Foreign Types

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

fn from_iter<I>(iter: I) -> Option<V> where
    I: IntoIterator<Item = Option<A>>, 

Takes each element in the Iterator: if it is None, no further elements are taken, and the None is returned. Should no None occur, a container with the values of each Option is returned.

Here is an example which increments every integer in a vector, checking for overflow:

use std::u16;

let v = vec![1, 2];
let res: Option<Vec<u16>> = v.iter().map(|&x: &u16|
    if x == u16::MAX { None }
    else { Some(x + 1) }
).collect();
assert!(res == Some(vec![2, 3]));

impl<T> FromIterator<T> for BinaryHeap<T> where
    T: Ord, 

fn from_iter<I>(iter: I) -> BinaryHeap<T> where
    I: IntoIterator<Item = T>, 

impl<T> FromIterator<T> for BTreeSet<T> where
    T: Ord, 

fn from_iter<I>(iter: I) -> BTreeSet<T> where
    I: IntoIterator<Item = T>, 

impl<K, V> FromIterator<(K, V)> for BTreeMap<K, V> where
    K: Ord, 

fn from_iter<T>(iter: T) -> BTreeMap<K, V> where
    T: IntoIterator<Item = (K, V)>, 

impl FromIterator<String> for String

fn from_iter<I>(iter: I) -> String where
    I: IntoIterator<Item = String>, 

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

fn from_iter<I>(it: I) -> Cow<'a, str> where
    I: IntoIterator<Item = String>, 

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

fn from_iter<I>(iter: I) -> LinkedList<T> where
    I: IntoIterator<Item = T>, 

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

fn from_iter<I>(iter: I) -> Vec<T> where
    I: IntoIterator<Item = T>, 

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

fn from_iter<I>(iter: I) -> String where
    I: IntoIterator<Item = &'a str>, 

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

fn from_iter<I>(it: I) -> Cow<'a, str> where
    I: IntoIterator<Item = &'b str>, 

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

fn from_iter<I>(it: I) -> Cow<'a, [T]> where
    I: IntoIterator<Item = T>, 

impl FromIterator<char> for String

fn from_iter<I>(iter: I) -> String where
    I: IntoIterator<Item = char>, 

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

fn from_iter<I>(it: I) -> Cow<'a, str> where
    I: IntoIterator<Item = char>, 

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

fn from_iter<I>(iter: I) -> String where
    I: IntoIterator<Item = Cow<'a, str>>, 

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

fn from_iter<I>(iter: I) -> String where
    I: IntoIterator<Item = &'a char>, 

impl<'a> FromIterator<HeaderView<'a>> for Headers

fn from_iter<I>(iter: I) -> Headers where
    I: IntoIterator<Item = HeaderView<'a>>, 

impl<S> FromIterator<S> for AcAutomaton<S, Dense> where
    S: AsRef<[u8]>, 

fn from_iter<T>(it: T) -> AcAutomaton<S, Dense> where
    T: IntoIterator<Item = S>, 

Create an automaton from an iterator of strings.

impl FromIterator<SslMode> for SslMode

fn from_iter<T>(iterator: T) -> SslMode where
    T: IntoIterator<Item = SslMode>, 

impl FromIterator<SslVerifyMode> for SslVerifyMode

fn from_iter<T>(iterator: T) -> SslVerifyMode where
    T: IntoIterator<Item = SslVerifyMode>, 

impl FromIterator<Flag> for Flag

fn from_iter<T>(iterator: T) -> Flag where
    T: IntoIterator<Item = Flag>, 

impl FromIterator<SslOption> for SslOption

fn from_iter<T>(iterator: T) -> SslOption where
    T: IntoIterator<Item = SslOption>, 

impl<'a> FromIterator<HeaderView<'a>> for Headers

fn from_iter<I>(iter: I) -> Headers where
    I: IntoIterator<Item = HeaderView<'a>>, 

impl<T> FromIterator<T> for Value where
    T: Into<Value>, 

fn from_iter<I>(iter: I) -> Value where
    I: IntoIterator<Item = T>, 

Convert an iteratable type to a Value

Examples

use serde_json::Value;

let v = std::iter::repeat(42).take(5);
let x: Value = v.collect();

use serde_json::Value;

let v: Vec<_> = vec!["lorem", "ipsum", "dolor"];
let x: Value = v.into_iter().collect();

use std::iter::FromIterator;
use serde_json::Value;

let x: Value = Value::from_iter(vec!["lorem", "ipsum", "dolor"]);

impl FromIterator<(String, Value)> for Map<String, Value>

fn from_iter<T>(iter: T) -> Map<String, Value> where
    T: IntoIterator<Item = (String, Value)>, 

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

fn from_iter<I>(iterable: I) -> SmallVec<A> where
    I: IntoIterator<Item = <A as Array>::Item>, 

impl FromIterator<OFlag> for OFlag

fn from_iter<T>(iterator: T) -> OFlag where
    T: IntoIterator<Item = OFlag>, 

impl FromIterator<MsFlags> for MsFlags

fn from_iter<T>(iterator: T) -> MsFlags where
    T: IntoIterator<Item = MsFlags>, 

impl FromIterator<MQ_OFlag> for MQ_OFlag

fn from_iter<T>(iterator: T) -> MQ_OFlag where
    T: IntoIterator<Item = MQ_OFlag>, 

impl FromIterator<Mode> for Mode

fn from_iter<T>(iterator: T) -> Mode where
    T: IntoIterator<Item = Mode>, 

impl FromIterator<QuotaValidFlags> for QuotaValidFlags

fn from_iter<T>(iterator: T) -> QuotaValidFlags where
    T: IntoIterator<Item = QuotaValidFlags>, 

impl FromIterator<InputFlags> for InputFlags

fn from_iter<T>(iterator: T) -> InputFlags where
    T: IntoIterator<Item = InputFlags>, 

impl FromIterator<CloneFlags> for CloneFlags

fn from_iter<T>(iterator: T) -> CloneFlags where
    T: IntoIterator<Item = CloneFlags>, 

impl FromIterator<MsFlags> for MsFlags

fn from_iter<T>(iterator: T) -> MsFlags where
    T: IntoIterator<Item = MsFlags>, 

impl FromIterator<SockFlag> for SockFlag

fn from_iter<T>(iterator: T) -> SockFlag where
    T: IntoIterator<Item = SockFlag>, 

impl FromIterator<EventFlags> for EventFlags

fn from_iter<T>(iterator: T) -> EventFlags where
    T: IntoIterator<Item = EventFlags>, 

impl FromIterator<SealFlag> for SealFlag

fn from_iter<T>(iterator: T) -> SealFlag where
    T: IntoIterator<Item = SealFlag>, 

impl FromIterator<MsgFlags> for MsgFlags

fn from_iter<T>(iterator: T) -> MsgFlags where
    T: IntoIterator<Item = MsgFlags>, 

impl FromIterator<SaFlags> for SaFlags

fn from_iter<T>(iterator: T) -> SaFlags where
    T: IntoIterator<Item = SaFlags>, 

impl FromIterator<EpollCreateFlags> for EpollCreateFlags

fn from_iter<T>(iterator: T) -> EpollCreateFlags where
    T: IntoIterator<Item = EpollCreateFlags>, 

impl FromIterator<FdFlag> for FdFlag

fn from_iter<T>(iterator: T) -> FdFlag where
    T: IntoIterator<Item = FdFlag>, 

impl FromIterator<LocalFlags> for LocalFlags

fn from_iter<T>(iterator: T) -> LocalFlags where
    T: IntoIterator<Item = LocalFlags>, 

impl FromIterator<ControlFlags> for ControlFlags

fn from_iter<T>(iterator: T) -> ControlFlags where
    T: IntoIterator<Item = ControlFlags>, 

impl FromIterator<EpollFlags> for EpollFlags

fn from_iter<T>(iterator: T) -> EpollFlags where
    T: IntoIterator<Item = EpollFlags>, 

impl FromIterator<OutputFlags> for OutputFlags

fn from_iter<T>(iterator: T) -> OutputFlags where
    T: IntoIterator<Item = OutputFlags>, 

impl FromIterator<MntFlags> for MntFlags

fn from_iter<T>(iterator: T) -> MntFlags where
    T: IntoIterator<Item = MntFlags>, 

impl FromIterator<FsFlags> for FsFlags

fn from_iter<T>(iterator: T) -> FsFlags where
    T: IntoIterator<Item = FsFlags>, 

impl FromIterator<FdFlag> for FdFlag

fn from_iter<T>(iterator: T) -> FdFlag where
    T: IntoIterator<Item = FdFlag>, 

impl FromIterator<SFlag> for SFlag

fn from_iter<T>(iterator: T) -> SFlag where
    T: IntoIterator<Item = SFlag>, 

impl FromIterator<WaitPidFlag> for WaitPidFlag

fn from_iter<T>(iterator: T) -> WaitPidFlag where
    T: IntoIterator<Item = WaitPidFlag>, 

impl FromIterator<SpliceFFlags> for SpliceFFlags

fn from_iter<T>(iterator: T) -> SpliceFFlags where
    T: IntoIterator<Item = SpliceFFlags>, 

impl FromIterator<MapFlags> for MapFlags

fn from_iter<T>(iterator: T) -> MapFlags where
    T: IntoIterator<Item = MapFlags>, 

impl FromIterator<ProtFlags> for ProtFlags

fn from_iter<T>(iterator: T) -> ProtFlags where
    T: IntoIterator<Item = ProtFlags>, 

impl FromIterator<MemFdCreateFlag> for MemFdCreateFlag

fn from_iter<T>(iterator: T) -> MemFdCreateFlag where
    T: IntoIterator<Item = MemFdCreateFlag>, 

impl FromIterator<Flags> for Flags

fn from_iter<T>(iterator: T) -> Flags where
    T: IntoIterator<Item = Flags>, 

impl<F> FromIterator<F> for FuturesUnordered<F> where
    F: Future, 

fn from_iter<T>(iter: T) -> FuturesUnordered<F> where
    T: IntoIterator<Item = F>, 

impl<F> FromIterator<F> for FuturesOrdered<F> where
    F: Future, 

fn from_iter<T>(iter: T) -> FuturesOrdered<F> where
    T: IntoIterator<Item = F>, 

Implementors

• impl<A, E, V> FromIterator<Result<A, E>> for Result<V, E> where
    V: FromIterator<A>, 
• impl<A> FromIterator<A> for VecDeque<A>
• impl<T, S> FromIterator<T> for HashSet<T, S> where
    S: BuildHasher + Default,
    T: Eq + Hash, 
• impl<K, V, S> FromIterator<(K, V)> for HashMap<K, V, S> where
    K: Eq + Hash,
    S: BuildHasher + Default, 
• impl<P> FromIterator<P> for PathBuf where
    P: AsRef<Path>,