Swift – Convert String to Integer

Swift – Convert String to Int

To convert a String value to Integer value in Swift, use Int() and Optional Value unwrapping.

The syntax to convert a String x to Integer is

Int(x)

Int() returns an Optional Integer value, and we can convert this to an Integer value using Optional Value Unwrapping !, as shown in the following.

var result = Int(str)
if result != nil {
    let x = result! //unwrap to Int
    //code
}

Examples

In this example, we take a String value in str and convert this value to Integer.

main.swift

var str = "256"
var result = Int(str)
if result != nil {
    let x = result! //unwrap to Int
    print(x)
}

Output

If the value in String cannot be converted to an Integer, Int() returns nil value. In that case, check if the value returned by Int() is not nil. Only if not nil, proceed with unwrapping the returned optional value.

main.swift

var str = "256 abc"
var result = Int(str)
if result != nil {
    let x = result! //unwrap to Int
    print(x)
} else {
    print("Result of Int() is nil.")
}

Output

Conclusion

In this Swift Tutorial, we have learned how to convert a String to Integer in Swift programming.