can i return two hashes from a soubroutine

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

I want to return two hashes from a subroutine
does not seem to work and gives this output
Use of uninitialized value in concatenation (.) or string at C:\scripts\perl\source\testhash.pl line 20.
test1 0 type-test2-0 value1-test2-0value1-test2-0
test1 1 type-test2-1 value1-test2-1value1-test2-1
test1 2 type-test2-2 value1-test2-2value1-test2-2
test1 3 type-test2-3 value1-test2-3value1-test2-3
test1 4 type-test2-4 value1-test2-4value1-test2-4
test1 5 type-test2-5 value1-test2-5value1-test2-5
test1 6 type-test2-6 value1-test2-6value1-test2-6
test1 7 type-test2-7 value1-test2-7value1-test2-7
Use of uninitialized value in concatenation (.) or string
at C:\scripts\perl\source\testhash.pl line 20.
Use of uninitialized value in concatenation (.) or string
at C:\scripts\perl\source\testhash.pl line 20. Use of uninitialized value in concatenation (.) or string
at C:\scripts\perl\source\testhash.pl line 20.
Use of uninitialized value in concatenation (.) or string
at C:\scripts\perl\source\testhash.pl line 20.
what is wrong in my code

#!/usr/bin/perl -w
use strict;
my %test1;
my %test2;
my $k;
(%test1,%test2) = &testsub;
foreach $k (sort keys %test1) {
 print " test1 $k $test1{$k}{'type'} $test1{$k}{'value1'}$test1{$k}{'v
+alue1'} \n";
}
foreach $k (sort keys %test2) {
 print " test1 $k $test2{$k}{'type'} $test2{$k}{'value1'}$test2{$k}{'v
+alue1'} \n";
}

sub testsub {
my $hasrows=0;
my %test1;
my %test2;

while ($hasrows < 5) {
    $test1{$hasrows} = {
       'type' => "type-test-$1hasrows",
       'value1' => "value1-test1-$hasrows",
       'value2' => "value2-test1-$hasrows"
    };
  $hasrows +=1;
}
$hasrows=0;
while ($hasrows < 8) {
    $test2{$hasrows} = {
       'type' => "type-test2-$hasrows",
       'value1' => "value1-test2-$hasrows",
       'value2' => "value2-test2-$hasrows"
    };
  $hasrows +=1;
}
return (%test1,%test2);
}
[download]

thks for your help
HarryC >/br>

20071029 Janitored by Corion: Changed </br> tags to <br/> tags, as per Writeup Formatting Tips

Comment on can i return two hashes from a soubroutine Select or Download Code

Replies are listed 'Best First'.
Re: can i return two hashes from a soubroutine by ikegami (Patriarch) on Oct 25, 2007 at 21:27 UTC
Subroutines can only return a scalar in scalar context. Subroutines can only return a list of scalars in list context. Subroutines can never return hashes or arrays. That leaves you with two options: 1) Return information that will allow you to rebuild the hashes and arrays you wish to return, and/or 2) Return references to the hashes and arrays you wish to return. This is very similar to arguments. Only a list of scalars can be passed to a subroutine as arguments. Hashes and arrays can never be passed to a subroutine as arguments. You have the same two options in that situation: 1) Pass information that will allow you to rebuild the hashes and arrays you wish to provide, and/or 2) Pass references to the hashes and arrays you wish to provide.	[reply]
Re: can i return two hashes from a soubroutine by jdporter (Paladin) on Oct 25, 2007 at 20:38 UTC
Of course, though you'll want to return them by reference. (Actually, you'll have to return at least the first one by reference.) `return( \%test1, \%test2 );` [download] and use the return values appropriately in the caller. A word spoken in Mind will reach its own level, in the objective world, by its own weight	[reply] [d/l]
Re: can i return two hashes from a soubroutine by thezip (Vicar) on Oct 25, 2007 at 20:44 UTC
You'll need to return references to your hashes from the sub, as in: `return(\%test1, \%test2);` In the caller, if you must, you can dereference the hashrefs by: `my ($test1,$test2) = &testsub; my %test1 = %$test1; my %test2 = %$test2;` [download] Where do you want them* to go today?*	[reply] [d/l] [select]
Re: can i return two hashes from a soubroutine by toolic (Bishop) on Oct 25, 2007 at 20:45 UTC
Use of uninitialized value in concatenation (.) or string at C:\scripts\perl\source\testhash.pl line 20. I believe you are getting this warning because you have a typo. Change: `'type' => "type-test-$1hasrows",` [download] to: `'type' => "type-test-$hasrows",` [download]	[reply] [d/l] [select]