How to capture multiple repeated groups?

Question

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 1

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]+)$

Answer 2

Just to provide additional example of paragraph 2 in the answer. I'm not sure how critical it is for you to get three groups in one match rather than three matches using one group. E.g., in groovy:

def subject = "HELLO,THERE,WORLD"
def pat = "([A-Z]+)"
def m = (subject =~ pat)
m.eachWithIndex{ g,i ->
  println "Match #$i: ${g[1]}"
}

Match #0: HELLO
Match #1: THERE
Match #2: WORLD

Answer 3

I think you need something like this....

b="HELLO,THERE,WORLD"
re.findall('[\w]+',b)

Which in Python3 will return

['HELLO', 'THERE', 'WORLD']