Convert nested array in swift to single dimensional array

Question

I have a structure like [[[ ]]] which I want to convert to [].

E.g. [ [ [ \"Hi\" ] ] ] into [ \"Hi\" ]

How

Answer 1

joined() returns (a lazy view of) the elements of an collection, concatenated. This can be applied repeatedly for deeper nested collections:

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

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

The outer Array() constructor builds an array from the sequence. Apart from that, no intermediate arrays are created.

If you just want to iterate over the nested array then the joined sequence is sufficient:

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