在 Swift 中展平数组 [英] Flatten an Array of Arrays in Swift
本文介绍了在 Swift 中展平数组的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
在 Swift 中是否有对应的 flatten
在 Scala、Xtend、Groovy、Ruby 和 co 中?
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]
当然我可以使用reduce,但那有点糟糕
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([], +)
flatMap
:
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())
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