Perl. Problem with HASH value

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

Hi!

I use perl 5.10.1_5 at FreeBSD and try execute this code:

#!/usr/bin/perl

use utf8;
use Encode;
use strict;
use warnings;
use Data::Dumper;

my $locale = "EN";
my $setSwitchName = "UNINSTALL";

my $content = {
           'EN' => {
                     'SWITCH' => {
                                   'INSTALL' => {
                                                  'ACTION' => 'a1',
                                                  'ICONID' => 'i1',
                                                  'CAPTION' => 'c1',
                                                  'DIZ' => 'd1'
                                                },
                                   'UNINSTALL' => {
                                                  'ACTION' => 'a2',
                                                  'ICONID' => 'i2',
                                                  'CAPTION' => 'c2',
                                                  'DIZ' => 'd2'
                                                }
                                 },
                     'ACTION' => 'a3',
                     'ICONID' => 'i3',
                     'CAPTION' => 'c3',
                     'DIZ' => 'd3'
                   }
         };

my $switchValues = $content->{$locale}->{'SWITCH'};
print ("switchValues=".Dumper($switchValues)."\n");

my $setSwitchValue = $switchValues->{$setSwitchName};
my $tmpContent = $setSwitchValue;
$tmpContent->{'SWITCH'} = $switchValues;
my $newContent->{$locale} = $tmpContent;
print ("newContent=".Dumper($newContent));
[download]

I wanna create new HASH with changed part defined by $setSwitchName, but when i look at th e dump of $newContent i see next:

newContent=$VAR1 = {
          'EN' => {
                    'SWITCH' => {
                                  'INSTALL' => {
                                                 'ACTION' => 'a1',
                                                 'ICONID' => 'i1',
                                                 'DIZ' => 'd1',
                                                 'CAPTION' => 'c1'
                                               },
                                  'UNINSTALL' => $VAR1->{'EN'}
                                },
                    'ACTION' => 'a2',
                    'ICONID' => 'i2',
                    'DIZ' => 'd2',
                    'CAPTION' => 'c2'
                  }
        };
[download]

Why the value of 'UNINSTALL' is $VAR1->{'EN'} ???

I Am doing something wrong or is this a problem in Perl or what?

Comment on Perl. Problem with HASH value Select or Download Code

Replies are listed 'Best First'.
Re: Perl. Problem with HASH value by choroba (Cardinal) on Dec 16, 2011 at 18:17 UTC
This is not a problem in Perl. You told Perl what to do: `$tmpContent->{'SWITCH'} = $switchValues;` [download] You probably meant this: `my $tmpContent = { %$setSwitchValue };` [download] i.e. do not assign a reference to the old value to tmpContent, but a reference to a newly created hash with the values you want to keep.	[reply] [d/l] [select]
Re^2: Perl. Problem with HASH value by breeze (Initiate) on Dec 16, 2011 at 20:12 UTC
big thanks! this is what i need exactly!	[reply]
Re: Perl. Problem with HASH value by Anonymous Monk on Dec 16, 2011 at 18:04 UTC
See Tutorials: References #!/usr/bin/perl -- use strict; use warnings; my @foo = 0..3; my @bar = 3..6; my %blah = ( foo => \@foo, stillfoo => \@foo, bar => \@bar ); $blah{"why YES, this too is foo"} = \@foo; $blah{"and this too is bar"} = \@bar; my $THIS_IS_FOO_TOO = \@foo; my $THIS_IS_BAR_TOO = \@bar; ## and now, lets modify $foo[1] five different ways $foo[1] .= ' you '; $blah{foo}[1] .= ' are '; $blah{stillfoo}[1] .= ' still '; $blah{"why YES, this too is foo"}[1] .= ' the '; $THIS_IS_FOO_TOO->[1] .= ' @foo '; print "$foo[1]\n"; __END__ [download] The output is 1 you are still the @foo See also http://learn.perl.org/books/beginning-perl/ and the Modern Perl Book	[reply] [d/l]