Regex Error

rjahrman has asked for the wisdom of the Perl Monks concerning the following question:

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Re: Regex Error by japhy (Canon) on May 20, 2004 at 01:50 UTC
Sounds like you don't even need a regex. `if (index($after, $scur) > -1) { # $after contains the text in $scur }` [download] _____________________________________________________ Jeff`[japhy]`Pinyan: Perl, regex, and perl hacker, who'd like a job (NYC-area) `s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;`	[reply] [d/l]
Re: Regex Error by beth (Scribe) on May 20, 2004 at 01:09 UTC
A variable can contain a regular expression, metacharacters and all, so you are correct about what perl is doing here: it's interpreting the dollar sign as the indicator for end-of-line. You can get the behavior you want by using \Q (quote) and \E (end, I guess). \E is optional: `if ($after =~ /\Q$scur/){ ...` [download] You can read more about this in perldoc perlre. (2004-05-20 fixed typo that swapped \U for \E)	[reply] [d/l]
Re: Regex Error by Nkuvu (Priest) on May 20, 2004 at 01:01 UTC
I think you want `\Q` and `\E`: `#!/usr/bin/perl use strict; my $cur = "\$foo"; my $after = "This is a \$foo test"; print "Match: '$after' contains '$cur'\n" if ($after =~ /\Q$cur\E/);` [download]	[reply] [d/l] [select]
Re: Regex Error by pbeckingham (Parson) on May 20, 2004 at 00:35 UTC
Try the following: `if ($after =~ /$scur/) { do something; }` [download] or if you want a literal `$` in the pattern: `if ($after =~ /\$scur/) { do something; }` [download]	[reply] [d/l] [select]
Re: Regex Error by rjahrman (Scribe) on May 20, 2004 at 00:42 UTC
I've already tried the first way (I also tried $after =~ $scur). And I don't want a literal dollar sign . . . the contents of $scur could change. ?	[reply]
Re: Re: Regex Error by pbeckingham (Parson) on May 20, 2004 at 00:57 UTC
If you've tried the first way and it didn't work, then I suspect that `$after` and/or `$scur` do not contain quite the data you expect. Can you confirm this? Are there newlines in either? Is case an issue? How about using: `my $pattern = "\\" . $cur; if ($after =~ /$pattern/) { do something; }` [download]	[reply] [d/l] [select]