character extract from string in swift

Question

I have a task to do something with a chess board. The input gives us a starting position of some chess figure. For example "b4" or "a6" or something like that. How can i decompose the input and make from it two integer numbers, like in C++:

string input;
cin>>input

int coord_x = input[0] - 'a';

int coord_y = input[1]

I cannot manage to do that in swift. I do something like:

let input : String=readLine()!
let characters = Array(input)

and then try to take the int but it doesnt work, no matter what i try... and what type is the content of the Array in swift?

Louis Lac · Accepted Answer · 2020-04-26 16:33:49Z

1

You can retrieve the c string representation like this:

let string = "a5"
let scalars = string.lowercased().cString(using: .ascii)!

let first = scalars[0]
let second = scalars[1]

It could be safer to retrieve the unicodeScalar characters instead:

let string = "a5".lowercased()
let characters = Array(string.unicodeScalars)

let first = characters[0].value - UnicodeScalar(unicodeScalarLiteral: "a").value

edited Apr 26, 2020 at 16:33

answered Apr 26, 2020 at 15:47

Louis Lac

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1 Comment

Louis Lac Over a year ago

Int8 is always representable to Int(64), just convert with Int(first).

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