Regex matchin -(lala)- problem

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

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Re: Regex matchin -(lala)- problem by zigdon (Deacon) on Oct 16, 2002 at 17:25 UTC
You have to quote the () in $skip, otherwise they're parsed as part of the regexp: `$file ="-(lala)-"; $skip ="-(lala)-"; print "$skip / $file\n"; if ($file =~ /\Q$skip\E/i) { print "matched!\n"; }` [download] See quotemeta. You could also use \ if your pattern is static, just watch out for the double quotes eating it up: `$skip = "-$lala$-"; # $skip is now -(lala)- compared with $skip = '-$lala$-'; # $skip is now -$lala$-` [download] -- Dan	[reply] [d/l] [select]
Re: Regex matchin -(lala)- problem by bigj (Monk) on Oct 16, 2002 at 17:32 UTC
`if ($file =~ /-$lala$-/) { ...` [download] will work, but `my $skip = "/-$lala$-/"; if ($file =~ /$skip/)` [download] won't work. The reason is the difference where the backslash is used. In the first case it is used in a regexp, where it protects the (), while in the second one, it is used in a string where it is interpreted as a simple () used in the regexp again as capturing characters. You can use one of the following workarounds: `my $skip = "/-\$lala\$-/"; # protect the backslash for itself if ($file =~ /$skip/) { ...` [download] `my $skip = '/-$lala$-/'; # use singe quotes if ($file =~ /$skip/) { ...` [download] `my $skip = "/-(lala\-/"; if ($file =~ /\Q$skip/) { ... # quote it in the regexp` [download] `my $skip = qr/-$lala$-/; # use precompiled regexps if ($file =~ /$skip/) { ...` [download] Greetings, Janek	[reply] [d/l] [select]