How to split an Int to its individual digits?

Question

I am trying to split an Int into its individual digits, e.g. 3489 to 3 4 8 9, and then I want to put the digits in an Int array.

I have already tried putting the num

Answer 1

You can use this

extension Int {

func numberOfDigits() -> Int {
    if abs(self) < 10 {
        return 1
    } else {
        return 1 + (self/10).numberOfDigits()
    }
}

func getDigits() -> [Int] {
    let num = self.numberOfDigits()
    var tempNumber = self
    var digitList = [Int]()

    for i in (0..<num).reversed() {
        let divider = Int(pow(CGFloat(10), CGFloat(i)))
        let digit = tempNumber/divider
        digitList.append(digit)
        tempNumber -= digit*divider
    }
    return digitList
}

}

Answer 2

You can use this:

// input -> "123456"
// output -> [1, 2, 3, 4, 5, 6]
// Get the string, convert it in an Array(), 
// use a loop (convert i in Int()), to add it into a container, then return it. Done! 

    func getDigitsFromString(for string: String) -> [Int]{
        let stringInt = Array(string)
        var array = [Int]()
        for i in stringInt {
            if let i = Int(String(i)) {
                array.append(i)
            }
        }
        return array
    }

Answer 3

You can try this:

var number = "123456"
var array = number.utf8.map{Int($0)-48}

You can make use of the utf8 property of String to directly access the ASCII value of the characters in the String representation of your number.

Answer 4

extension Int {
    var digits : [Int] {
        var result = [Int]()
        var remaining = abs(self)
        while remaining > 0 {
            result.insert(remaining % 10, at: 0)
            remaining /= 10
        }
        return result
    }
}

Answer 5

this code works:

var number = "123456"
var array = number.utf8.map{Int(($0 as UInt8)) - 48}

this might be slower:

var array = number.characters.map{Int(String($0))!}

and if your number is less or equal than Int.max which is 9223372036854775807 here is the fastest variant (and if your number>Int.max you can split your long string that represents your number into 18-digit groups to make this variant work on large strings)

var array2 = [Int]()
var i = Int(number)!
while i > 0 {array2.append(i%10); i/=10}
array2 = array2.reverse()

Answer 6

A solution without having to convert the int to string....

Example

1234%10 = 4 <-
1234/10 = 123
123%10 = 3 <-
123/10 = 12
12%10 = 2 <- 
12/10 = 1
1%10 = 1 <-

var num = 12345
var arrayInt = [Int]()
arrayInt.append(num%10)
while num >= 10 {
  num = num/10
  arrayInt.insert(num%10, at: 0)
}