stream-reduce

Rust中流的reduce函数

[dependencies]
stream-reduce = "0.1"

lib.rs:

此crate为Streams提供了一个类似fold的reduce函数，但没有初始值。如果流为空，函数返回包含None的Future，否则返回Some(value)。

基于David Tolnay的reduce crate for iterators。

示例

use stream_reduce::Reduce;
use futures::stream;

async {
    // Reduce a non-empty stream into Some(value)
    let v = vec![1usize, 2, 3, 4, 5];
    let sum = stream::iter(v).reduce(|a, b| async move { a + b }).await;
    assert_eq!(Some(15), sum);

    // Reduce an empty stream into None
    let v = Vec::<usize>::new();
    let product = stream::iter(v).reduce(|a, b| async move { a * b }).await;
    assert_eq!(None, product);
}