I find kotlins regex kind of complicated. Usually I use it to find the first match, but it seems I d...

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[Paul Woitaschek]

I find kotlins regex kind of complicated. Usually I use it to find the first match, but it seems I don't understand something about how it is supposed to work because the code looks kind of awkward:

regex.find(line)?.groupValues?.getOrNull(1)

Is this the correct way to find the first match of a regex result?

[Arian Stolwijk]

Maybe use destructured to make it easier?

[Paul Woitaschek]

But why does it have the whole string as the first match?

[araqnid]

The destructured projection explicitly doesn’t, val (g) = match.destructured will assign the first match group to g. Although that’s not so convenient when you’re starting from an optional match.
regex.find(input)?.let { it.groupValues[1] } would be what I’d write

[Michael de Kaste]

@Paul Woitaschek regex engines explicitly use the first capture group to the full match. This isn't "kotlin's" regex that's 'kind of complicated'.

.NET, javascript and Java (languages I worked with) all have group 0 as the full match, that's just how regex works.

[nkiesel]

this would not be required if your regexp always matches the whole line. But consider Regex("my \\w+").find("hello my dear friend")?.value which returns my dear. W/o that you always would have to have at least one () in every regex to get a matched string back