modify an array within a function does not work

Question

I call a function to process and modify an array. But the array does not change at all. Looks like a Swift major bug ???

var Draw_S = [String]();
var Draw_E =          


        

Answer 1

The arrays inside alter_them are a copy of the originals.

Use inout to modify the original arrays:

func alter_them(inout data: [String], inout data2: [String]){
    for (i, _) in data.enumerate(){
        data[i] = "1"
    }
    for (i, _) in data2.enumerate(){
        data2[i] = "2"
    }
}

alter_them(&Draw_S, data2: &Draw_E)