Re^2: reg ex NOT

Remember that using * means to match zero or more times and that ? matches zero or one times, and that you can always match zero times. When you match zero times, you don't prevent anything from not matching:

print "Matched" if "dont" =~ m/don(?:(?!t).)*/;
[download]

You could anchor it so that nothing after it could match:

print "Matched" if "dont" =~ m/don(?:(?!t).)*$/;
[download]

It's easier just to type the negated character class for that position, though:

print "Matched" if "dont" =~ m/don[^t]/;
[download]

--
brian d foy <brian@stonehenge.com>
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Re^3: reg ex NOT by ikegami (Patriarch) on Jun 16, 2006 at 01:33 UTC
Aye, the construct I posted needs to be anchored (but not necessarily using `^` and `$`). It may be a waste to use that construct for single characters, but it's useful (necessary) for the use I described in my original post (i.e. To matche a sequence of characters that does not contain anything that matches a specified regexp). For example, `/<table>(?:(?!<\/table>).)*<\/table>/` [download] (Not the best example, cause tables can be nested in HTML and for other reasons, but you get the idea.)	[reply] [d/l] [select]

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Re^3: reg ex NOT
by ikegami (Patriarch) on Jun 16, 2006 at 01:33 UTC

Aye, the construct I posted needs to be anchored (but not necessarily using ^ and $). It may be a waste to use that construct for single characters, but it's useful (necessary) for the use I described in my original post (i.e. To matche a sequence of characters that does not contain anything that matches a specified regexp). For example,

/<table>(?:(?!<\/table>).)*<\/table>/
[download]

(Not the best example, cause tables can be nested in HTML and for other reasons, but you get the idea.)

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