How to loop through hash of array and convert into hash with key and value.

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

Hi Monks,

I am new to PERL, stuck on looping through the hash of array and convert hash with key and value please.

Have ...


$VAR1 = [
          {
            'name' => 'Tim',
            'total' => 4,
            'months' => 1,
            'days' => 3
          },
          {
            'total' => 22,
            'name' => 'Adam',
            'days' => 22
          },
          {
            'name' => 'Keas',
            'total' => 114,
            'months' => 5,
            'days' => 107,
            'test' => 2
          }
];
[download]

How to loop through this and convert into like below ?


$VAR1 = {
          'Tim' => {
                          'total' => 4,
                          'months' => 1,
                          'days' => 3
                           },
             'Adam' =>  {
                             'total' => 22,
                              'days' => 22
                        },
              'Keas' => {
                             'total' => 114,
                             'months' => 5,
                             'days' => 107,
                             'test' => 2
                              }
              };
[download]

Thanks in advanced.

Comment on How to loop through hash of array and convert into hash with key and value. Select or Download Code

Replies are listed 'Best First'.
Re: How to loop through hash of array and convert into hash with key and value. by stevieb (Canon) on Dec 28, 2019 at 02:35 UTC
What you actually have there is an array of hashes. Since the `delete` function returns the item that was deleted, we can use it directly in the assignmnent: `use warnings; use strict; use Data::Dumper; my $aref = [ { 'name' => 'Tim', 'total' => 4, 'months' => 1, 'days' => 3 }, { 'total' => 22, 'name' => 'Adam', 'days' => 22 }, { 'name' => 'Keas', 'total' => 114, 'months' => 5, 'days' => 107, 'test' => 2 } ]; my $href; $href->{delete $_->{name}} = $_ for @$aref; print Dumper $href;` [download] Output: `$VAR1 = { 'Adam' => { 'days' => 22, 'total' => 22 }, 'Keas' => { 'total' => 114, 'test' => 2, 'days' => 107, 'months' => 5 }, 'Tim' => { 'total' => 4, 'days' => 3, 'months' => 1 } };` [download]	[reply] [d/l] [select]
Re^2: How to loop through hash of array and convert into hash with key and value. by Sami_R (Sexton) on Dec 28, 2019 at 11:01 UTC
Elegant solutions, thanks.	[reply]
Re: How to loop through hash of array and convert into hash with key and value. by NetWallah (Canon) on Dec 28, 2019 at 02:33 UTC
Verified working code: `$VAR1 = { map { $_->{name} => $_ } @$VAR1 };` [download] Don't be shy about asking specific, detailed questions on how/why that works, after researching the "map" function. "From there to here, from here to there, funny things are everywhere." -- Dr. Seuss	[reply] [d/l]
Re^2: How to loop through hash of array and convert into hash with key and value. by Sami_R (Sexton) on Dec 28, 2019 at 11:11 UTC
Mapping worked after modifying like... `my $VAR3 = { map { delete $_->{name} => $_ } @$VAR1 };` [download] Thanks.	[reply] [d/l]
Re^2: How to loop through hash of array and convert into hash with key and value. by stevieb (Canon) on Dec 28, 2019 at 02:42 UTC
Unfortunately, this doesn't address removing the `name` from the inner hash references.	[reply] [d/l]
Re: How to loop through hash of array and convert into hash with key and value. by NetWallah (Canon) on Dec 28, 2019 at 02:40 UTC
A more "traditional" approach: `my $VAR2; for my $h (@$VAR1){ $VAR2->{ $h->{name} } = $h; } print Dumper \$VAR2;` [download] "From there to here, from here to there, funny things are everywhere." -- Dr. Seuss	[reply] [d/l]
Re^2: How to loop through hash of array and convert into hash with key and value. by Sami_R (Sexton) on Dec 28, 2019 at 11:15 UTC
Great solutions, thank you so much.	[reply]