Make regexp shorter

Question

I have the following text: var avarb avar var varb var. What I want to do is to extract only "direct" var occurrences. The above string contains 3 of them.

While playing with rubular I made up the following Regexp: /\A(var)|\s(var)\s|(var)\z/. Is there a way to simplify it, in order to use var substring in regexp only once?

score 5 · Accepted Answer · answered Apr 16 '11 at 14:10

5

Try this one using word boundaries:

 /\bvar\b/

answered Apr 16 '11 at 14:10

Alexander Ivanov

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Marcel Jackwerth · Answer 2 · 2011-04-16T14:18:27.243

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Either use Alexanders version or

/(^|\s)(var)($|\s)/       # or:
/(?:^|\s)(var)(?:$|\s)/   # (?: ) will prevent capturing

edited Apr 16 '11 at 14:18

answered Apr 16 '11 at 14:11

Marcel Jackwerth

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Thanks for "prevent capturing", didn't know that – oldhomemovie Apr 17 '11 at 06:54

score 0 · Answer 3 · edited Apr 17 '11 at 23:11

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/\s+(var)\+/ would seem sufficient?

edited Apr 17 '11 at 23:11

Andrew Grimm

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answered Apr 16 '11 at 14:10

Dartoxian

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score 0 · Answer 4 · answered Apr 16 '11 at 14:10

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If I understand you correctly, you can use lookaheads and lookbehinds:

/(?<=^|\s)(var)(?=$|\s)/

answered Apr 16 '11 at 14:10

Håvard

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Make regexp shorter

4 Answers4