convert user input to array of Ints in swift

Question

I'm trying to make a simple iOS game to learn programming in swift. The user inputs a 4 digits number in a text field (keyboard type number pad if that matters) and my program should take that 4 digits number and put each digit in an array. basically I want something like

userInput = "1234"

to become

inputArray = [1,2,3,4]

I know converting a string to an array of characters is very easy in swift

var text : String = "BarFoo"
var arrayText = Array(text)
//returns ["B","a","r","F","o","o"]

my problem is I need my array to be filled with Integers, not characters. If I convert the user input to an Int, it becomes a single number so if user enters "1234" the array gets populated by [1234] and not [1,2,3,4]

So I tried to treat the user input as a string, make an array of its characters and, then loop through the elements of that array, convert them to Ints and put them into a second array, like:

var input : String = textField.text
var inputArray = Array(input)
var intsArray = [Int]()

for var i = 0; i < inputArray.count ; i++ {
    intsArray[i] = inputArray[i].toInt()
}

but it doesn't compile and gives me the error: 'Character' does not have a member named 'toint'

What am I doing wrong?

If you want 1234 instead of 1,2,3,4 then you don't need an array for that. 1234 is a single int value. — Mehul Patel
– Mehul Patel, Commented Dec 16, 2014 at 9:09

Kirsteins · Accepted Answer · 2014-12-16 09:32:40Z

4

You could use:

let text : String = "123a"
let digits = Array(text).map { String($0).toInt()! }
// Crash if any character is not int

But it will crash if input is not valid.

You can validate by checking the result of toInt():

let text : String = "1234"
var digits = Array(text).reduce([Int](), combine: { (var digits, optionalDigit) -> [Int] in
    if let digit = String(optionalDigit).toInt() {
        digits.append(digit)
    }

    return digits
})

if countElements(text) == digits.count {
    // all digits valid
} else {
    // has invalid digits
}

answered Dec 16, 2014 at 9:32

Kirsteins

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2 Comments

Iacopo Boccalari Over a year ago

Thanks a lot, the first piece of code is enough because the user can only enter integers since I set the text field keyboard type to "Number Pad".

Mehul Patel Over a year ago

Yes, this is the right way to get characters from string.

travis · Accepted Answer · 2016-11-17 03:30:13Z

1

Here is a much simpler solution for future users

let text : String = "12345"
var digits = [Int]()
for element in text.characters 
{
    digits.append(Int(String(element))!)
}

answered Nov 17, 2016 at 3:30

travis

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Comments

lukszar · Accepted Answer · 2016-09-07 13:54:40Z

0

Convert String into [Int] extension - Swift Version

I put below extensions which allow you to convert String into [Int]. It's long version, where you can see what happen in each line with your string.

extension String {

    func convertToIntArray() -> [Int]? {

        var ints = [Int]()
        for char in self.characters {
            if let charInt = char.convertToInt() {
                ints.append(charInt)
            } else {
                return nil
            }
        }
        return ints
    }
}


extension Character {

    func convertToInt() -> Int? {
        return Int(String(self)) ?? nil
    }
}

answered Sep 7, 2016 at 13:54

lukszar

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