Re: Usage of hashes with hashes when mulitple values are present

Your code gives me the error

Odd number of elements in hash assignment at ./t4.pl line 6.

Hashes are defined this way:

my %hash = ( somekey => somevalue, ...);
[download]

So your code should read:

#!/usr/bin/perl -w

use strict;
use Data::Dumper;

my %w =  (     Sub =>
                    {
                        'rbscells' =>
                                        'UtranCell=RNC16-4-1',
                                        'UtranCell=RNC16-4-2',
                                        'UtranCell=RNC16-4-3'
                    }
)
;

print Dumper(%w);
[download]

Now when you look at the output of Data::Dumper, you can see, that what you probably wanted to be an array (the three strings starting with "UtranCell*") are in fact a hash value and another hash key + value:

$VAR1 = 'Sub';
$VAR2 = {
          'rbscells' => 'UtranCell=RNC16-4-1',
          'UtranCell=RNC16-4-2' => 'UtranCell=RNC16-4-3'
        };
[download]

However, you can't just put an array definition inside a hash - from perldsc:

The most important thing to understand about all data structures in Perl--including multidimensional arrays--is that even though they might appear otherwise, Perl @ARRAYs and %HASHes are all internally one-dimensional. They can hold only scalar values (meaning a string, number, or a reference). They cannot directly contain other arrays or hashes, but instead contain references to other arrays or hashes.

So another change, to define an array reference:

...
'rbscells' => [
                                         'UtranCell=RNC16-4-1',
                                         'UtranCell=RNC16-4-2',
                                         'UtranCell=RNC16-4-3' ,
                                        ]
...
[download]

You can access the elements of the array as always, via index starting from 0 or with foreach like this:

foreach my $element (@{$w{Sub}->{rbscells}})
{
    print $element . "\n";
}
[download]

To understand nested data structures in perl, please refer to perldsc, especially the chapter about "Hashes of Arrays".

Comment on Re: Usage of hashes with hashes when mulitple values are present Select or Download Code

Replies are listed 'Best First'.
Re^2: Usage of hashes with hashes when mulitple values are present by Bhagya (Initiate) on Nov 28, 2013 at 08:59 UTC
Hi , Please find this piece of code as follows :: `# Get the list of cells, which has same frequency and SC Id # $t = $w{$_}{frequency} .':'. $w{$_}{sc}; push(@{$w{$t}{cells}}, $_);` [download] . Here w is a hash variable . for each cell we will be retrieving its corresponding frequency and sc value in following format repectively : `$w{$_}{frequency} and $w{$_}{sc}` [download] The above piece of code will collect all the cells which fall in that frequency and sc value .. SO when we give data dumper we will get as follows :: `'-1:130' => { 'cells' => [ 'SubNetwork=ONRM_ROOT_MO_R,SubNet +work=RNC12,MeContext=RNC12,ManagedElement=1,RncFunction=1,UtranCell=R +NC12-8-2' 'SubNetwork=ONRM_ROOT_MO_R,SubNetwork=RNC12,MeContext=RNC12,ManagedEle +ment=1,RncFunction=1,UtranCell=RNC12-8-8' ] },` [download] Please let me know how to retrieve the values taht are in array .	[reply] [d/l] [select]
Re^3: Usage of hashes with hashes when mulitple values are present by lune (Pilgrim) on Dec 02, 2013 at 11:05 UTC
It is hard to follow you, as you omit certain information, that would make it much easiear to answer your question. You should just post a runnable piece of complete code, that shwow your problem. Please read ?node_id=510718 As you just want to know how to access the data, why bother about the way you create the data structure? Here, I just initialized a hash with the data you provided. Then I can access the elements of the arrayref: #!/usr/bin/perl -w use strict; use Data::Dumper; my %w = ( '-1:130' => { 'cells' => [ 'SubNetwork=ONRM_ROOT_MO_R,SubNetwork=RNC12,MeContext=RNC1 +2,ManagedElement=1,RncFunction=1,UtranCell=RNC12-8-2', 'SubNetwork=ONRM_ROOT_MO_R,SubNetwork=RNC12,MeContext=RNC1 +2,ManagedElement=1,RncFunction=1,UtranCell=RNC12-8-8' ], }, ); #print Dumper(\%w); # access one element by index: first = 0 print "Element 0: " . $w{'-1:130'}{'cells'}->[0] . "\n"; print "\n"; # access all available in a foreach loop foreach my $element (@{$w{'-1:130'}{'cells'}}) { print $element . "\n"; } [download]	[reply] [d/l]
Re^4: Usage of hashes with hashes when mulitple values are present by Bhagya (Initiate) on Dec 03, 2013 at 04:06 UTC
Thanks lune and all . It was helpful for me to understand the usage of hash .	[reply]


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