Creates a new integer value from the given string and radix.

init?<S>(_ text: S, radix: Int = 10) where S : StringProtocol



The ASCII representation of a number in the radix passed as radix.


The radix, or base, to use for converting text to an integer value. radix must be in the range 2...36. The default is 10.


The string passed as text may begin with a plus or minus sign character (+ or -), followed by one or more numeric digits (0-9) or letters (a-z or A-Z). Parsing of the string is case insensitive.

let x = Int("123")
// x == 123

let y = Int("-123", radix: 8)
// y == -83
let y = Int("+123", radix: 8)
// y == +83

let z = Int("07b", radix: 16)
// z == 123

If text is in an invalid format or contains characters that are out of bounds for the given radix, or if the value it denotes in the given radix is not representable, the result is nil. For example, the following conversions result in nil:

Int(" 100")                       // Includes whitespace
Int("21-50")                      // Invalid format
Int("ff6600")                     // Characters out of bounds
Int("zzzzzzzzzzzzz", radix: 36)   // Out of range