in reply to Relative Merits of References

It would make a difference if you wanted to pass two hashes to a sub.


#!/usr/bin/perl

use strict;
use warnings;

my $h1 = {
 one => 1,
 two => 2,
};

my $h2 = {
 three => 3,
 four => 4,
};

my_sub($h1, $h2);

sub my_sub {
 my ($h1, $h2) = @_;
 print "$_ $h1->{$_}\n" for keys %{$h1};
 print "$_ $h2->{$_}\n" for keys %{$h2};
}

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In these circumstances refs are, imo, the only way to go. :-)

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Re^2: Relative Merits of References
by Unanimous Monk (Sexton) on May 11, 2006 at 15:04 UTC
    Or alternatively:

    #!/usr/bin/perl

use strict;
use warnings;

my %h1 = (
 one => 1,
 two => 2,
);

my %h2 = (
 three => 3,
 four => 4,
);

my_sub(\%h1, \%h2);

sub my_sub {
my ($ref1, $ref2) = @_;
my %h1 = %{$ref1};
my %h2 = %{$ref2};

# Or "my %h1 = %{(shift)};" will work too, but I don't really like it.

 print "$_ $h1{$_}\n" for keys %h1;
 print "$_ $h2{$_}\n" for keys %h2;
}

    [download]

    if you want to keep the hash. This is really the only way to go :)

[reply]
[d/l]

      Now you're making an expensive copy of a hash. You could just be using the references with: 

      my ($r1, $r2) = @_;
...
print "$_ $h1{$_}\n" for keys %$r1;
print "$_ $h2{$_}\n" for keys %$r2;

      [download]

      Update:Thanks again David, yes, I meant: 

      print "$_ $r1->{$_}\n" for keys %$r1;
print "$_ $r2->{$_}\n" for keys %$r2;

      [download]



      pbeckingham - typist, perishable vertebrate.
[reply]
[d/l]
[select]
        print "$_ $h1{$_}\n" for keys %$r1;

        ITYM $h1->{$_}.

        --
        David Serrano

[reply]

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