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

Hi, I'm having some troubles to extract an expresiion from a $line. The type of expression is, for example: 
KP_what_I_want (space)
or
KP_what_I_want(
or
KP_what_I_want (
or
KP_what_I_want +
etc...

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I'm using: 
my ($exp) = 
    $line =~ m/ 
                    KP_          # Required 
                    (.*)            # Capture Desired Output
                    (?:\s)?      # Optional - Do not capture
            (?:\()?         # Optional - Do not capture
     /xi;

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It's not working... it extracts the all expression ( without the KP_) Any ideas? Thanks, Kepler

Replies are listed 'Best First'.
Re: String extract 2
by farang (Chaplain) on Jul 24, 2014 at 12:35 UTC

    You can use a negated character class to match up until the included chars in the class are found. 

    #!/usr/bin/env perl
use strict;
use warnings;
use feature 'say';

my @test_cases = ( 'KP_what_I_want(but_not_this',
                   'KP_what_I_want nor_this', 
                   'KP_ nor_any_of_this',
                   'and this will not match',
                 ); 
             
for my $line (@test_cases) {

    my ($exp) = $line =~ m/ KP_   # Required.
                         ( [^ (]* ) # Capture until space 
                                    # or left paren.
                         /xi;

    if (defined $exp) {say "<$exp>"}
        else {say 'NO MATCH'};
}
__END__
<what_I_want>
<what_I_want>
<>
NO MATCH

    [download]

[reply]
[d/l]
Re: String extract 2
by jellisii2 (Hermit) on Jul 24, 2014 at 12:03 UTC
[reply]

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