Check if a Double value is of a certain format with Regex

Question

I have been trying to write a function that validates if a given Double is a number between 1-100. And only whole numbers, so something like 1.5 would not be allowed. Allowed would be 1,2,3,...,100. I'm using the following regex for that ->

"^([1-9][0-9]?$)|^100$"

however, even if i input 100, my function never gives me back true. In which way is my regex wrong?

this is the rest of my code

func validate(input: Double) -> Bool {

        let regex = "^([1-9][0-9]?$)|^100$"

        let inputTest = NSPredicate(format: "SELF MATCHES %@", regex)
        return inputTest.evaluate(with: String(input)) 
}

the input has to be a Double.

Why are you using regex and a predicate for this? Convert the string to a `Double`. If that succeeds, then check the value of the `Double`. — rmaddy, Dec 04 '16 at 18:45
BTW - why `Double`? Sounds like you only want integers. `3.14` is a double between 1 and 100. — rmaddy, Dec 04 '16 at 18:46
Have a look [here](http://stackoverflow.com/q/31396301/1971013) What you're doing is overcomplicated. — meaning-matters, Dec 04 '16 at 18:56

score 0 · Accepted Answer · answered Dec 04 '16 at 18:58

0

You don't need a regex or a predicate. Simply do some basic checking as follows:

func validate(input: Double) -> Bool {
    return input >= 1 && input <= 100 && round(input) == input;
}

answered Dec 04 '16 at 18:58

rmaddy

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Check if a Double value is of a certain format with Regex

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