CODEWITHSUNDEEP
regexparsingkotlin
michpohl
michpohl

Reputation: 1125

Kotlin: Can't parse regular expression containing multiple back slashes - Why do I have a "Unclosed group"?

I am trying to match the anchor link that is "triple-escaped" in this string example:

blablabla some text <a href=\\\"#anchor\\\"> some more text

This is my regular expression:

href=(\\\\\\)(\"#.*)(\\\\\\)\"

If I test it on regex101.com it works, but I need to do this filtering in Kotlin, which I thought I could do like this:

fun findEscapedAnchors(text: String): String {
    val pattern = "href=(\\\\\\)(\"#.*)(\\\\\\)\""
    val regex = pattern.toRegex()
    val matches = regex.find(text)

    // do something with the matches
}

First of all, if I paste this String into my code (in Android Studio), it gets auto-escaped even more, but it doesn't work. If I edit it to match the above String, it complains that there's an unclosed group. I thought I could maybe put it in triple quotations to not have to escape characters, but that also failed. What am I doing wrong?

Upvotes: 1

Views: 347

Answers (1)

michpohl
michpohl

Reputation: 1125

I have figured it out myself: A raw string (triple quotations) was indeed the way to go, but Regex apparently still needs the character escapes in the string. Before, I had them removed, because I thought that's how raw strings work, but I was wrong. So it works now with this: 

val regex = """href=(\\\\\\)(\"#.*)(\\\\\\)\"""".toRegex()

Upvotes: 1

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