Trait rayon::iter::ParallelDrainRange

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pub trait ParallelDrainRange<Idx = usize> {
    type Iter: ParallelIterator<Item = Self::Item>;
    type Item: Send;

    fn par_drain<R: RangeBounds<Idx>>(self, range: R) -> Self::Iter;
}

Expand description

ParallelDrainRange creates a parallel iterator that moves a range of items from a collection while retaining the original capacity.

Types which are not indexable may implement ParallelDrainFull instead.

Required Associated Types

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type Iter: ParallelIterator<Item = Self::Item>

The draining parallel iterator type that will be created.

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type Item: Send

The type of item that the parallel iterator will produce. This is usually the same as IntoParallelIterator::Item.

Required Methods

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fn par_drain<R: RangeBounds<Idx>>(self, range: R) -> Self::Iter

Returns a draining parallel iterator over a range of the collection.

When the iterator is dropped, all items in the range are removed, even if the iterator was not fully consumed. If the iterator is leaked, for example using std::mem::forget, it is unspecified how many items are removed.

Examples

use rayon::prelude::*;

let squares: Vec<i32> = (0..10).map(|x| x * x).collect();

println!("RangeFull");
let mut vec = squares.clone();
assert!(vec.par_drain(..)
           .eq(squares.par_iter().copied()));
assert!(vec.is_empty());
assert!(vec.capacity() >= squares.len());

println!("RangeFrom");
let mut vec = squares.clone();
assert!(vec.par_drain(5..)
           .eq(squares[5..].par_iter().copied()));
assert_eq!(&vec[..], &squares[..5]);
assert!(vec.capacity() >= squares.len());

println!("RangeTo");
let mut vec = squares.clone();
assert!(vec.par_drain(..5)
           .eq(squares[..5].par_iter().copied()));
assert_eq!(&vec[..], &squares[5..]);
assert!(vec.capacity() >= squares.len());

println!("RangeToInclusive");
let mut vec = squares.clone();
assert!(vec.par_drain(..=5)
           .eq(squares[..=5].par_iter().copied()));
assert_eq!(&vec[..], &squares[6..]);
assert!(vec.capacity() >= squares.len());

println!("Range");
let mut vec = squares.clone();
assert!(vec.par_drain(3..7)
           .eq(squares[3..7].par_iter().copied()));
assert_eq!(&vec[..3], &squares[..3]);
assert_eq!(&vec[3..], &squares[7..]);
assert!(vec.capacity() >= squares.len());

println!("RangeInclusive");
let mut vec = squares.clone();
assert!(vec.par_drain(3..=7)
           .eq(squares[3..=7].par_iter().copied()));
assert_eq!(&vec[..3], &squares[..3]);
assert_eq!(&vec[3..], &squares[8..]);
assert!(vec.capacity() >= squares.len());