character recognition

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

Dear Monks,

I have a variable which I would like to use for character recognition but it does not seem to work. Could you check ? Thanks

my $song = "cool"; 

if (my $line =  /score*"$song"/){
...
}
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Comment on character recognition Download Code

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Re: character recognition by hipowls (Curate) on Mar 06, 2008 at 12:28 UTC
Your regular expression is probably not doing what you think it is. It matches a line that has a literal 'scor', zero or 'e's then a literal '"cool"'. You probably mean to use '.' to match zero or more characters (except newline). `if ( my $line =~ /score.$song/ ) { ... }` [download] but without seeing the input you expect to match I can't be sure.	[reply] [d/l]
Re: character recognition by moritz (Cardinal) on Mar 06, 2008 at 12:28 UTC
Describe what you want to match, then we can help you. Your regex will match scor"cool", score"cool", scoree"cool ", scoreee"cool" etc. Maybe you meant `m/score.*$song/`? BTW I recommend perlretut as an introduction, or "Mastering Regular Rexpressions" if you'd rather like a book.	[reply] [d/l]
Re: character recognition by olus (Curate) on Mar 06, 2008 at 12:45 UTC
Besides what has already been said, you should notice that you are not testing for a match of `$line` to the regexp. You assigning to `$line` the result of the match of `$_`, if already defined, to the regexp. Maybe a typo, but you should use `=~`.	[reply] [d/l] [select]