How to use regular expressions in Swift 3?

Question

I wanted to follow this tutorial to learn about NSRegularExpression in Swift, but it has not been updated to Swift 3. When I open the playground with the examples they provide, I get several errors being one of them the call:

let regex = NSRegularExpression(pattern: pattern, options: .allZeros, error: nil)

I've seen that now that initializer throws an exception so I changed the call, but that .allZeros does not seem to exist anymore. I don't find any tutorial or example with an equivalent of that in Swift 3, could somebody tell me what option should now replace such .allZeros option?

This may helps http://stackoverflow.com/q/27880650/6521116 – LF00 May 08 '17 at 04:29 — LF00, May 08 '17 at 04:29

score 7 · Accepted Answer · answered Dec 09 '16 at 18:08

I believe .allZeros was to be used when no other options applied.

So with Swift 3, you can pass an empty list of options or leave out the options parameter since it defaults to no options:

do {
    let regex = try NSRegularExpression(pattern: pattern, options: [])
} catch {
}

or

do {
    let regex = try NSRegularExpression(pattern: pattern)
} catch {
}

Note that in Swift 3 you don't use the error parameter any more. It now throws.

score 5 · Answer 2 · answered Dec 09 '16 at 18:09

You can use []:

let regex = try! NSRegularExpression(pattern: pattern, options: [])

which is also the default value, so you can omit this argument:

let regex = try! NSRegularExpression(pattern: pattern)

The easiest way to find this out is to command+click jump to the methods definition:

public init(pattern: String, options: NSRegularExpression.Options = []) throws

How to use regular expressions in Swift 3?

2 Answers2