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())
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