regex in swift is not working with this example?

Question

I am trying to use Regex expressions but this does not work and I don't understand why. The println is not showing up in the output. I followed this tutorial to use this class:

class Regex {
  let internalExpression: NSRegularExpression
  let pattern: String

  init(_ pattern: String) {
    self.pattern = pattern
    var error: NSError?
    self.internalExpression = NSRegularExpression(pattern: pattern, options: .CaseInsensitive, error: &error)
  }

  func test(input: String) -> Bool {
    let matches = self.internalExpression.matchesInString(input, options: nil, range:NSMakeRange(0, countElements(input)))
    return matches.count > 0
  }
}

And this other tutorial to create the Regex.

The code returns the text when I do not use Regex. If I do use it, the println does not appear. I tried "(/([a-z]+)|([0-9]+)/ig)$" and "/([a-z]+)|([0-9]+)/ig$" but none of them work.

func textFieldDidEndEditing(textField: UITextField) {
        println("end editing")

        if let match = textField.text.rangeOfString("/([a-z]+)|([0-9]+)/ig$", options: .RegularExpressionSearch) {
            println("\(match) is probably f**ked off and left as a f**king bastard")
        }

        if Regex("/([a-z]+)|([0-9]+)/ig").test(textField.text){
            println("yes")
            textField.text = textField.text.uppercaseString
        }
    }

What is your input for textField.text? Could you give us some examples of what you want to match the regex, and what you don't want to match? — Jojodmo
– Jojodmo, Commented Mar 1, 2015 at 19:15
I get a compiler error in above self.internalExpression =... : not unwrapped. — qwerty_so
– qwerty_so, Commented Mar 1, 2015 at 19:23
@Thomas Kilian You should add a ! at the end of the line to unwrap Optional value. See the 'Implicitly Unwrapped Optionals' section in The Swift Programming Language self.internalExpression = NSRegularExpression(pattern: pattern, options: .CaseInsensitive, error: &error)! — devxoul
– devxoul, Commented Mar 1, 2015 at 19:25
@devxoul Thx for moving it as a comment, but my comment was just meant as a comment to the OP :-) I know that I have to add ! — qwerty_so
– qwerty_so, Commented Mar 1, 2015 at 21:47

Alexey Pichukov · Accepted Answer · 2015-03-01 19:28:38Z

3

In this case, you do not need to use (/ ..... /ig)$, so try this:

   if let match = textField.text.rangeOfString("([a-z]+)|([0-9]+)", options: .RegularExpressionSearch) {
                println("\(match) is bla bla bla...")
            }

It will be work and return the range of the first occurrence of a given string

answered Mar 1, 2015 at 19:28

Alexey Pichukov

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3 Comments

Paul Over a year ago

thanks, what about case insensitive? Is there a better way than ( [a-z]+ | [A-Z]+ ) ?

Alexey Pichukov Over a year ago

If you mean the way to find uppercase simbols, then [A-Z] is the standard choice

TomSawyer Over a year ago

anyway to still use i , g , u ... flags in pattern?

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