I want to find matches for string example but not www.example. What is the regex I can use? I've tried the following but it doesn't work:
(?!www.\)example
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Ivar
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Shivanand Sharma
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Could just use `/^example$/` to only catch example – clearshot66 Sep 11 '17 at 18:56
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1Check this [^www.]example – dwij Sep 11 '17 at 18:59
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`[^www\.]example` matches `"example` in `alt="example.com"`. Note it matches the starting quote. – Shivanand Sharma Sep 11 '17 at 19:04
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@dwij: no it's wrong, you didn't well understand character classes. – Casimir et Hippolyte Sep 11 '17 at 20:05
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@CasimiretHippolyte yeah, it is enough to have one w in that case. am I right? – dwij Sep 12 '17 at 01:58
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1@dwij: yes, character classes are only sets of characters, so `[^.w]`, `[^w.]` and `[^www.]` are the same character class. – Casimir et Hippolyte Sep 12 '17 at 10:29
1 Answers
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If you just try to match a string that does start with example but not with www.example than it would be as easy as:
^example
Otherwise you can use a negative lookbehind:
(?<!\bwww\.)\bexample\b
The \b in here is a word boundery, meaning that it matches it, as long as it is not part of a string. (In other words if it isn't followed by or following any A-Za-z characters, a number or an underscore.)
As mentioned by @CasimiretHippolyte this does still match strings like www.othersubdomain.example.com.
Casimir et Hippolyte
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Ivar
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@ShivanandSharma [This answer](https://stackoverflow.com/a/2973495/479156) goes in a bit deeper into the positive/negative lookahead/lookbehind if you want to get some good examples. – Ivar Sep 11 '17 at 19:16
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@CasimiretHippolyte I've updated by answer to make it at least a bit better. Thanks for pointing it out. – Ivar Sep 11 '17 at 21:12