RegEx non-capturing group issue

Question

Why following return ["vddv"] instead of ["dd"]:

"aaavddv".match(/(?:v).*(?:v)/)

alan · Accepted Answer · 2012-05-23T12:39:01.177

4

(?:v) # matches 'v' this is a non-capturing group, not a lookbehind
.*    # matches 'dd'
(?:v) # matches 'v' this is a non-capturing group, not a lookahead

Non-capturing groups still participate in the match. Perhaps you want a lookahead/behind? But Javascript does not support lookbehind.

edited May 23 '12 at 12:39

answered May 23 '12 at 12:33

alan

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score 3 · Answer 2 · answered May 23 '12 at 12:33

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"aaavddv".match(/(?:v)(.*)(?:v)/)[1]

the whole match is correctly vddv but if you want to match only dd you need to use a capturing group (and look at element [1])

answered May 23 '12 at 12:33

Fabrizio Calderan

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score 3 · Answer 3 · answered May 23 '12 at 12:34

3

/(?:v).*(?:v)/ specifies expression v(number of characters)v

answered May 23 '12 at 12:34

ravi

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RegEx non-capturing group issue

3 Answers3