Sun751 has asked for the wisdom of the Perl Monks concerning the following question:

In below code I am iterating my hash and checking if value of res.ldlibrarypath(key) equals to content of $target, Actually I want to substitute some of the content of the value so I am doing substitution, But can any one tell me how can I update my hash after that substitution? 
    for my $hashref($HR_wnt,$HR_unx,$HR_component)
    {
        for my $id (keys %$hashref)
        {
            if ($id eq 'res.ldlibrarypath')
            {
                if ($$hashref{$id} =~ /=\//)
                {
                $$hashref{$id}=~ s/\/opt\/app\/$target.*?://;

                }
            }
        }
    }

[download]
Any one have any suggestion, please Cheers

Replies are listed 'Best First'.
Re: Update hash value
by GrandFather (Saint) on Jun 25, 2009 at 08:43 UTC

    Your two if statements are incompatible - they can never both be true, so no substitution can happen. Aside from that the code works. Consider:

    use strict;
use warnings;

my $HR_wnt = {'res.ldlibrarypath' => 'Flobble=/opt/app/Flobble:'};
my $HR_unx;
my $HR_component;
my $target = 'Flobble';

for my $hashref ($HR_wnt, $HR_unx, $HR_component) {
    for my $id (keys %$hashref) {
        if ($id eq 'res.ldlibrarypath') {
            if ($$hashref{$id} =~ /=\//) {
                $$hashref{$id} =~ s/\/opt\/app\/$target.*?://;
            }
        }
    }
}

print $HR_wnt->{'res.ldlibrarypath'};

    [download]

    Prints:

    Flobble=

    [download]

    Update actually there is nothing wrong with the two if statements. Bogus comment struck, working sample data supplied, commented code reinstated and sample output corrected.

    True laziness is hard work
[reply]
[d/l]
[select]
Re: Update hash value
by moritz (Cardinal) on Jun 25, 2009 at 11:48 UTC
    What you're doing is called "clubbing somebody to death with a loaded Uzi": instead of if iterating over all hash keys and looking op if one is equal to another key, you can simply look up the second key: 
    my $key = 'res.ldlibrarypath';
for my $hashref($HR_wnt,$HR_unx,$HR_component) {
    if (exists $hashref->{$key} && $hashref->{$key} =~ m{/}) {
         $hashref->{$key} =~ s{/opt/app/$target.*?:}{}
    }
}

    [download]

    Your hash is updated after that substitution if the regex matched, so I don't quite understand what your question is about.

[reply]
[d/l]
      Oh I didn;t know its get updated after substitution!!! thanks any way Cheers
[reply]

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