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Home: Perl Programming Help: Beginner:
A question about qr() operator

 


moroshko
Novice

Jul 10, 2008, 1:51 PM

Post #1 of 4 (895 views)
A question about qr() operator Can't Post
Hello Gurus !

Can someone tell me please why this program:

Code
   
 
#!/usr/bin/perl 
use warnings; 
use strict;  
 
my $r = qr/^line2/;  
 
my $s = <<STR; 
line1 
line2 
STR  
 
if ($s =~ /$r/m) { 
 print "Match"; 
} else { 
 print "No Match"; 
}

prints "No Match", while this program:

Code
   
 
#!/usr/bin/perl 
use warnings; 
use strict;  
 
my $r = qr/^line2/m;  
 
my $s = <<STR; 
line1 
line2 
STR  
 
if ($s =~ /$r/) { 
 print "Match"; 
} else { 
 print "No Match"; 
}

prints "Match" as desired ?

Why the first program doesn't match ??

Thanks in advance !


KevinR
Veteran


Jul 10, 2008, 4:46 PM

Post #2 of 4 (889 views)
Re: [moroshko] A question about qr() operator [In reply to] Can't Post
Your code prints "match" in both examples. I tested with activeperl 5.008.
-------------------------------------------------


moroshko
Novice

Jul 11, 2008, 2:00 AM

Post #3 of 4 (880 views)
Re: [KevinR] A question about qr() operator [In reply to] Can't Post
Strange...

I work with Perl 5.10.0.

Anybody else ?


KevinR
Veteran


Jul 11, 2008, 2:19 AM

Post #4 of 4 (879 views)
Re: [moroshko] A question about qr() operator [In reply to] Can't Post
it is strange because both regexps are the same. In one you turn on the "m" modifier in the saved regexp and in the other you just add it to the end of the regexp. They should both work the same as far as I know. If I remove the "m" completely then I get "No Match" as expected. Ask on www.perlmonks.com and post back here if you get an explanation.
-------------------------------------------------


(This post was edited by KevinR on Jul 11, 2008, 2:22 AM)

 
 


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