Matching a scalar variable

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

Hi monks, I'm new to perl programming, I'm trying to write a small program that opens a text file with some phrases and then try to match it with another string. The problem is that it never matches. Why? I know that this code can be optimized, any suggestion is welcome.

open $FILE , "<", "db.txt" or print "Unable to open file";
@idstring = <$FILE>;
$count = 0;
while ($idstring[$count]) {
$string = $idstring[$count];
if ($msg =~ m/.*$string.*/i) {
print "$idstring[$count] found";
}
$count++;
}
close $FILE;
[download]

Comment on Matching a scalar variable Download Code

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Re: Matching a scalar variable by jethro (Monsignor) on Jul 31, 2009 at 17:56 UTC
It probably finds nothing because there is a \n at the end of each line you read from a text file. Adding `chomp(@idstring);` or `chomp $string;` will take care of that Also if $string has regex special characters in it, the result will be quite different from what you expect. Use \Q and \E to escape the special characters I would suggest using foreach instead of while. Looks much cleaner that way and you don't need a $count variable: `foreach $string (@idstring) { chomp($string); if ($msg =~ m/.\Q$string\E./i) { print "$string found"; last; } }` [download] Update: Removed reference to $count in my loop, thanks to ssandv for spotting it	[reply] [d/l] [select]
Re: Matching a scalar variable by jwkrahn (Abbot) on Jul 31, 2009 at 18:21 UTC
You probably want something more like this: `open my $FILE , "<", "db.txt" or print "Unable to open 'db.txt' $!"; while ( my $string = <$FILE> ) { if ( $msg =~ /$string/i ) { print "$string found\n"; } } close $FILE;` [download]	[reply] [d/l]
Re: Matching a scalar variable by alexm (Chaplain) on Jul 31, 2009 at 21:30 UTC
Aside from the other comments by fellow monks, you may need to perform the match the other way around (`$string =~ m/$msg/i`). It mostly depends on what you want to achieve.	[reply] [d/l]
Re: Matching a scalar variable by Anonymous Monk on Jul 31, 2009 at 17:45 UTC
perldoc -f index `if ( -1 != index lc $msg, lc $lidstring[$count] ){ print "$msg found\n"; }` [download]	[reply] [d/l]