Re: Regex to capture every readable character except COMMA

Basically you can make it a two-step method as well which might not be the most elegant/efficient solution but at least it's working and it's damn simple.

#!/usr/bin/perl -w

use warnings;
use strict;

my $var = "abc,d";

if($var =~ /,/)
{
    print "not matches \n";
}
elsif($var =~ /(.*)/)
{
    print "matches \n Captured: $1\n";
}

$var = "abcd";

if($var =~ /,/)
{
    print "not matches \n";
}
elsif($var =~ /(.*)/)
{
    print "matches \n Captured: $1\n";
}

exit 0;
[download]

Output:

not matches
matches
 Captured: abcd
[download]

Comment on Re: Regex to capture every readable character except COMMA Select or Download Code

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Re^2: Regex to capture every readable character except COMMA by AnomalousMonk (Archbishop) on Jan 09, 2014 at 19:02 UTC
`if($var =~ /,/) { print "not matches \n"; } elsif($var =~ /(.)/) { print "matches \n Captured: $1\n"; }` [download] The intent here seems to be to capture the entire string if it contains no comma. But `$var` already holds the entire string! Why 'capture' it again? Furthermore, a confounding subtlety lurks at the heart of the seemingly simple, innocent `/(.)/` regex: the `.` (dot) metaoperator matches everything except a newline: it will only capture up to the first newline, if present. You have just built a bug into your code. (This subtlety is the rationale for the PBP injunction to always use the `/s` "dot matches all" modifier with every regex.)	[reply] [d/l] [select]

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Re^2: Regex to capture every readable character except COMMA
by AnomalousMonk (Archbishop) on Jan 09, 2014 at 19:02 UTC

if($var =~ /,/) { print "not matches \n"; } elsif($var =~ /(.*)/) { print "matches \n Captured: $1\n"; }
[download]

The intent here seems to be to capture the entire string if it contains no comma. But $var already holds the entire string! Why 'capture' it again?

Furthermore, a confounding subtlety lurks at the heart of the seemingly simple, innocent /(.*)/ regex: the . (dot) metaoperator matches everything except a newline: it will only capture up to the first newline, if present. You have just built a bug into your code. (This subtlety is the rationale for the PBP injunction to always use the /s "dot matches all" modifier with every regex.)

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