在 Swift 中展平一个数组

Flatten an Array of Arrays in Swift(在 Swift 中展平一个数组)

问题描述

在 Scala、Xtend、Groovy、Ruby 和 co 中 flatten 在 Swift 中是否有对应物?

Is there a counterpart in Swift to flatten in Scala, Xtend, Groovy, Ruby and co?

var aofa = [[1,2,3],[4],[5,6,7,8,9]]
aofa.flatten() // shall deliver [1,2,3,4,5,6,7,8,9] 

当然我可以为此使用 reduce，但这有点糟糕

of course i could use reduce for that but that kinda sucks

var flattened = aofa.reduce(Int[]()){
    a,i in var b : Int[] = a
    b.extend(i)
    return b
}

推荐答案

Swift >= 3.0

Swift >= 3.0

减少:

let numbers = [[1,2,3],[4],[5,6,7,8,9]]
let reduced = numbers.reduce([], +)

平面地图:

let numbers = [[1,2,3],[4],[5,6,7,8,9]]
let flattened = numbers.flatMap { $0 }

加入:

let numbers = [[1,2,3],[4],[5,6,7,8,9]]
let joined = Array(numbers.joined())

这篇关于在 Swift 中展平一个数组的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持编程学习网！