RE: RE: Re: How do you match

You can't "append" it per se. You can't just say you want part of a regexp to match and another part to fail for the thing to succeed. Regular expressions are meant to match something, not "not" match. There's a negative lookahead thing (?!pattern) but that wasn't meant for what you're trying to do. You need to design your regular expression to succeed, even if you intend to negate its results when you're done (like with unless or !~).

Perhaps if you give us a few lines of input and tell us what is supposed to match, and if so, what part of that string you expect your regexp to pull out, and we can try and point you in the right direction (or even write it).

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RE: RE: RE: Re: How do you match by Limo (Scribe) on Sep 29, 2000 at 00:57 UTC
Ok, here's (hopefully) a more complete example: Example strings to match: `confederation-as-router: 1 2345 atlanta1-cr1 confederation-as-router: 1 2345 atlanta1-cr2 confederation-as-router: 1 2345 atlanta1-cr3 confederation-as-router: 1 2345 atlanta1-cr4 confederation-as-router: 1 2345 atlanta1-cr5 confederation-as-router: 1 2345 atlanta1-cr6 confederation-as-router: 1 2345 atlanta1-sr1` [download] open (FILE2, $file_2) or die "Couldn't open file: $!"; while (<FILE2>) { if ($_ =~ s/^confederation-as-router\:\W+\d\W+\d+\W//) { push(@file2, $_); } } </CODE> Currently, the regex will return: `atlanta1-cr1 atlanta1-cr2 atlanta1-cr3 atlanta1-cr4 atlanta1-cr5 atlanta1-cr6 atlanta1-sr1` [download] Based upon the above example, I want it to ONLY return: `atlanta1-sr1` [download] Is that clearer?	[reply] [d/l] [select]
RE: RE: RE: RE: Re: How do you match by Fastolfe (Vicar) on Sep 29, 2000 at 01:04 UTC
It might be simplest to do this: `print if !/cr\d$/ && $_ = (split)[3];` [download] You're basically breaking apart by spaces anyway, and if you can assume that each line will follow this pattern, it might be simplest to use split and only use a regular expression to be sure you're working with the right line. Even if you do use a regular expression like yours, it's probably easiest to break it apart anyway: `if (!/cr\d$/ && s/^confederation-as-router:\W+\d\W+\d\W//) { ... }` [download] or even `if (!/cr\d$/ && ($host, $last) = (split)[0,3]) { print $last if $host eq 'confederation-as-router:'; }` [download]	[reply] [d/l] [select]
(tye)Re: How do you match by tye (Sage) on Sep 29, 2000 at 01:04 UTC
Don't do that with a single regex. `while( <FILE> ) { if( s/^confederation-as-router\:\W+\d\W+\d+\W// && ! /cr\d$/ ) { push(@file2, $_); } }` [download] - tye (but my friends call me "Tye")	[reply] [d/l]
RE: (tye)Re: How do you match by Adam (Vicar) on Sep 29, 2000 at 01:10 UTC
Why not? `while( <FILE> ) { push @file2, $1 if m/^confederation-as-router:\W+\d\W+\d+\W(?!.cr\d ++)$/; }` [download] Although I bet you could improve on that further... reducing the . to something more specific. Update: I missed the negation in that. oops. I've added it to my regex. Thanks runrig and Tye for pointing that out to me. (For those who missed it, I forgot the ?!)	[reply] [d/l]