Using a Variable as a Match Expression

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

Hello Monks, i have Question about using variables in RegEx and escaping characters in this variables.
I have a

$find_file = '/home/camel/file';
[download]

and a list of files with it size

@list_of_file = ('/home/camel/file 42',
                 '/home/camel/file2 43',
                    ...
[download]

and now i want to find the $find_file in @list_of_files if i try

foreach $line (@list_of_files){
    if ($line =~ /$find_file/){
              print ($line);
           }
}
[download]

it can't find it, i think because of the not escaped slashes in $find_file
Have i to escape all regex control chars? Or is there an other way to do this?
Thanks
heinrich

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Re: Using a Variable as a Match Expression by wind (Priest) on Feb 16, 2011 at 17:45 UTC
quotemeta or \Q..\E will fix your problem with special characters if you want to use a regex. Should probably add some boundary requirements though as well: `foreach $line (@list_of_files){ if ($line =~ /^\Q$find_file\E\s/){ print ($line); } }` [download]	[reply] [d/l]
Re^2: Using a Variable as a Match Expression by Anonymous Monk on Feb 16, 2011 at 18:54 UTC
Thanks!	[reply]
Re: Using a Variable as a Match Expression by ikegami (Patriarch) on Feb 16, 2011 at 17:30 UTC
Use «`use strict; use warnings;`»!!	[reply] [d/l]
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Re: Using a Variable as a Match Expression by MidLifeXis (Monsignor) on Feb 16, 2011 at 17:46 UTC
Personally, I would use a different data structure for your @list_of_file: `%list_of_file = ( '/home/camel/file' => 42, ...);` and then `defined $list_of_file{$find_file}`. However, given the data structures that you have, may I suggest looking at grep and index? --MidLifeXis	[reply] [d/l] [select]