Re: Regex negative word

Of course, there are several ways to "skin a cat" (sorry :D)

Update: just acknowledging the fact that (as has been pointed out) this solution doesn't actually work. I won't bother changing the code, but rather leave it there as an example of how _not_ to do it ;)

#!/usr/bin/perl -wl
use strict;

while (<DATA>) {
    chomp;
    print "$_ matched" if /^[^(?:cat)]/;
}

__DATA__
cat dog
dog cat
frog cat dog
mouse dog cat
cat dog elephant
[download]

Prints:

dog cat matched
frog cat dog matched
mouse dog cat matched
[download]

Cheers,
Darren :)

Comment on Re: Regex negative word Select or Download Code

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Re^2: Regex negative word by GrandFather (Saint) on Mar 30, 2006 at 04:13 UTC
That is not doing what you think. Consider: `use strict; use warnings; while (<DATA>) { print "matched $_" if /^[^cat)(?:]/; } __DATA__ cat dog dog cat aardvark ant catnip dogbone frog cat dog mouse dog cat cat dog elephant can of worms` [download] Prints: `matched dog cat matched frog cat dog matched mouse dog cat` [download] The following code excludes beginning cats and insists that dogs end: `use strict; use warnings; while (<DATA>) { print "matched $_" if /^(?!cat\b).*(?=\bdog$)/; } __DATA__ cat dog dog cat catnip dogbone aardvark ant frog cat dog can of worms` [download] Prints: `matched frog cat dog` [download] DWIM is Perl's answer to Gödel	[reply] [d/l] [select]
Re^2: Regex negative word by pKai (Priest) on Mar 30, 2006 at 06:51 UTC
McDarren, your codes fails, because there is no such thing as complex grouping inside character classes (apart form ranges denoted by `-`). So especially your `(?:cat)` in there is not a single entity saying "c followed by a followed by t", but refers to the 7 characters it consists of. Grandfather saw this, but obscured the point in his reply somewhat by reordering that 7 chars. But you can use your code with his `__DATA__` and still see that lines beginning with "a" or any "c" (not only that reading "cat") will yield `no match`! The way to solve the problem of the OP is to use look-ahead-assertions, as demonstrated by Grandfather in both his replies.	[reply] [d/l] [select]
Re^2: Regex negative word by zer (Deacon) on Mar 30, 2006 at 03:44 UTC
this works!	[reply]