How to check if a string contains an int? -Swift

Simple Swift 4 version using rangeOfCharacter method from String class:

    let numbersRange = stringValue.rangeOfCharacter(from: .decimalDigits)
    let hasNumbers = (numbersRange != nil)

You can use Foundation methods with Swift strings, and that's what you should do here. NSString has built in methods that use NSCharacterSet to check if certain types of characters are present. This translates nicely to Swift:

var str = "Hello, playground1"

let decimalCharacters = CharacterSet.decimalDigits

let decimalRange = str.rangeOfCharacter(from: decimalCharacters)

if decimalRange != nil {
    print("Numbers found")
}

If you're interested in restricting what can be typed, you should implement UITextFieldDelegate and the method textField(_:shouldChangeCharactersIn:replacementString:) to prevent people from typing those characters in the first place.

This method is what i use now for checking if a string contains a number

func doStringContainsNumber( _string : String) -> Bool{

        let numberRegEx  = ".*[0-9]+.*"
        let testCase = NSPredicate(format:"SELF MATCHES %@", numberRegEx)
        let containsNumber = testCase.evaluateWithObject(_string)

        return containsNumber
        }

If your string Contains a number it will return true else false. Hope it helps