在swift中将嵌套数组转换为单维数组

Question

我有一个像[[[ ]]]这样的结构，我想将其转换为[]。

E.g. [ [ [ "Hi" ] ] ]分成[ "Hi" ]

我该如何在Swift中做到这一点？

Answer 1

以这种方式使用reduce(_:_:)与你的数组。

let array = [[["One","Two","Three"],["Four","Five"]],[["Six"]]] 
let newArray = array.reduce([]) { $0 + $1.reduce([]){ $0 + $1 } } 
print(newArray) //["One", "Two", "Three", "Four", "Five", "Six"] 

Answer 2

joined()返回（的懒惰视图）的集合中的元素，级联。这可以反复 更深嵌套集合被应用：

let arr = [ [ [ "A", "B" ], ["C"] ], [ [ "D", "E" ], ["F"] ] ] 

let flattened = Array(arr.joined().joined()) 
print(flattened) // ["A", "B", "C", "D", "E", "F"] 

外Array()构造函数建立从所述序列的阵列。 除此之外，没有创建中间数组。

如果你只是想遍历嵌套数组然后加入 序列足以：

for elem in arr.joined().joined() { 
    print(elem) 
} 

Answer 3

您可以使用加入成为

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

Answer 4

这正是flatMap（）的作用：

let arr = [ [ [ "A", "B" ], ["C"] ], [ [ "D", "E" ], ["F"] ] ] 

// each call reduces the array by one dimension 

let flattened = arr.flatMap{$0}.flatMap{$0} 

// returns ["A", "B", "C", "D", "E", "F"]