ZeddiOS

2차원배열을 1차원으로 만드는 방법 (Flatten a Array of Arrays in Swift) let arr : [[Int]] = [[1,2,3],[4,5,6],[7,8,9]]let useJoined = Array(arr.joined())let useflatMap = arr.flatMap{$0}let useReduce = arr.reduce([],+)//[1,2,3,4,5,6,7,8,9]