How to capture multiple repeated groups?

regex swift nsregularexpression regex-greedy regex-group
phbelov picture phbelov · May 3, 2016 · Viewed 117.7k times · Source

I need to capture multiple groups of the same pattern. Suppose, I have a following string:

HELLO,THERE,WORLD

And I've written a following pattern 

^(?:([A-Z]+),?)+$

What I want it to do is, capture every single word, so that Group 1 is : "HELLO", Group 2 is "THERE" and Group 3 is "WORLD" What my regex is actually capturing only the last one, which is "WORLD".

I'm testing my regular expression here and I want to use it with Swift (maybe there's a way in Swift to get intermediate results somehow, so that I can use them?)

UPDATE: I don't want to use split. I just need to now how to capture all the groups that have matched the pattern, not only the last one.

Answer

Byte Commander picture Byte Commander · May 3, 2016

With one group in the pattern, you can only get one exact result in that group. If your capture group gets repeated by the pattern (you used the + quantifier on the surrounding non-capturing group), only the last value that matches it gets stored.

You have to use your language's regex implementation functions to find all matches of a pattern, then you would have to remove the anchors and the quantifier of the non-capturing group (and you could omit the non-capturing group itself as well).

Alternatively, expand your regex and let the pattern contain one capturing group per group you want to get in the result:

^([A-Z]+),([A-Z]+),([A-Z]+)$

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