in reply to pass a hash to subroutine

As sauoq said, you could use a reference, which is probably the best way. You could also do this though: 
#! perl -w

%a = (qw{ 
good orange
good apple}
);

TEST(%a);
sub TEST{
my %h = @_;
foreach (keys %h){
    print $_;
}
}

[download]

Note using @_ where you had used $_[0] - that converts the entire array of parameters into a hash.

This is because the function receives a list of param, value, param, value.., which is stored in @_. By doing %h = @_; you put this into a hash with the first, third, fifth etc values as keys, and the second, fourth, sixth etc as values.

--------------------------------------------------------------

"If there is such a phenomenon as absolute evil, it consists in treating another human being as a thing."

John Brunner, "The Shockwave Rider".

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Re^2: pass a hash to subroutine
by benlaw (Scribe) on Nov 07, 2005 at 14:29 UTC
    Thanks for all "rapid" reply, the case solved

    But once more, if i want pass 2 or more hashes to subroutine, is it the same?

[reply]
      If you want to pass 2 or more hashes to a subroutine, you really need to use references. Have a look at perldoc perlref, but basically the syntax is:

      my %hashA = ( orange=>'good',
              apple=>'bad' );

my %hashB = ( here=>'today',
              gone=>'tomorrow' );

myfunction(\%hashA,\%hashB); # send references to the hashes

sub myfunction
{
  my $hashrefA = shift; # (or $_[0])
  my $hashrefB = shift; # (or $_[1])

  my %hashA = %$hashrefA; # treat the refs as hashes and
  my %hashB = %$hashrefB; # copy the contents

  $hashA{extravalue} = "change seen in the subroutine only";
  $hashrefA->{extravalue} = "change seen in the main program";

}

      [download]

      Following on from sauoqs comments, with that syntax, %hashA and %hashB in the subroutine are still copies of the original hashes. If you want to manipulate the original hashes and have the changes seen by the main part of the program, you will have to manipulate the hashrefs. I've included an example of each in the snippet above. If all you want to do is e.g. print them out, the copies might be less unwieldy to work with, if you're not familiar with reference syntax.

      --------------------------------------------------------------

      "If there is such a phenomenon as absolute evil, it consists in treating another human being as a thing."

      John Brunner, "The Shockwave Rider".

[reply]
[d/l]
[select]
      But once more, if i want pass 2 or more hashes to subroutine, is it the same?
      It was already in my answer, (although I minimally updated it silently for added clarity). Minimal example using a prototype: 
      #!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper;

sub foo (\%\%) {
    Dumper @_;
}

my %a=(foo => 1, bar =>2);
my %b=(%a, bax => 3);
print foo %a, %b;

__END__

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