in reply to Re: Hash reference as a parameter
in thread Hash reference as a parameter

I am a beginner in Perl. Please correct me if I am wrong!
I want to do something like the following, so that I can alter only some values of the hash and call the function again and again. I am not sure whether the same thing can be done using a 'list' as suggested in the previous post. 
#!/usr/bin/perl

use strict;
use Data::Dumper;

my %input = {foo => 'bar', oof => 'wha'};
my_sub(\%input);

$input{foo} = 'bar1';
my_sub(\%input);

sub my_sub {
    my $ref = shift;

    my %args = (
        foo => 'oop',
        pah => 'meh',
        oof => 'off',
        %{$ref}
    );

    warn Dumper(\%args);
}

[download]

Replies are listed 'Best First'.
Re^3: Hash reference as a parameter
by saberworks (Curate) on Sep 12, 2005 at 21:45 UTC
    Hrm, interesting question. It seems more like you want a global hash which gets reset to the default values each time the function is called with the exception of the values you pass in. I still don't think a reference is the way to go, but if it works, meh. What about this: 
    #!/usr/bin/perl

use strict;

use Data::Dumper;

my %hash = ();

my_sub(foo => 'bar', oof => 'wha');
my_sub(pah => 'eek');

sub my_sub {
    %hash = (
        foo => 'oop',
        pah => 'meh',
        oof => 'off',
        @_
    );

    warn Dumper(\%hash);
}

    [download]
[reply]
[d/l]
      Thanks for your time. But this is not the solution that I wanted!

      My idea is very simple. If the user creates the input parameters as a hash then he can alter the hash at any time and call the function. This is what I mean by the following statements. 
      my %input = {foo => 'bar', oof => 'wha'};
my_sub(\%input);

$input{foo} = 'bar1';
my_sub(\%input);

      [download]
[reply]
[d/l]
        So, in this case the code I posted first works fine, right? What I am confused about is why you want to pass things like this: 
        my_sub(\%hash);

        [download]
        instead of like this: 
        my_sub(%hash);

        [download]
        But, it really doesn't matter, if the solution works for you just use it :)

        Hrm, do you want the changes to be cumulative or to reset each time?
[reply]
[d/l]
[select]

In Section Seekers of Perl Wisdom