Perl - How to add rows in a hash inside a loop?

Question

Iam trying to create a simple array KEY => VALUE from a json response, here's my results when I dump the array but the keys are not what Im excpecting:

$VAR1 = 'expectedvalue1';
$VAR2 = 'expectedvalue2';
$VAR3 = 'expectedvalue3';

and here's my code that I found some part of it here (some comments says that there's backslash missing)

my %result = ();
foreach my $row (@json_response){
  $result{ $row->{"json_key"} } = $row->{"json_value"};
}
print Dumper(%result);

While I'm trying to get

expectedkey1 = expectedvalue1
expectedkey2 = expectedvalue2
expectedkey3 = expectedvalue3

Edit : I made a mistake in the names of keys.

I didn't read the full article you've linked. What you're seeing as your output is Data::Dumper taking a list of values, and assuming each one is one variable passed in. Because hashes in Perl are essentially lists of key/value pairs, they get turned into an argument list when passed to Dumper, so you get this $VAR1 stuff. Run print Dumper \%result to pass a reference to Data::Dumper, and you'll see something like $VAR1 = { "foo" => "bar", ... }. But that doesn't explain why your output doesn't have the keys as variables. Please edit and include the JSON you are parsing, and how. — simbabque
– simbabque, Commented Jun 3, 2020 at 11:22
The json is correct, I printed in the loop and show the expected key values, and when I did the print Dumper \%result it showed the expected result O.o well post your answer I'll accept it.. thank you — Imad BELHAUSS
– Imad BELHAUSS, Commented Jun 3, 2020 at 11:29
The problem we couldn't help you was a typo in your question. That's why I asked to see the data. Your question is well written, but it was incomplete. In the future please include a minimal reproducible example in your questions. I didn't answer but wrote a guess in a comment because it was just that, a guess. — simbabque
– simbabque, Commented Jun 3, 2020 at 14:00

Adrian · Accepted Answer · 2020-06-03 11:27:48Z

2

Are you trying to get key => value and key/value have the same values?

If you're looking for that, maybe this can help you

#!/usr/bin/perl -w

use strict;
use Data::Dumper;

my @array_items = qw(expectedvalue1 expectedvalue2 expectedvalue3);
my %hash_example;

foreach my $value (@array_items) {
        push(@{$hash_example{$value}}, $value);
}

print Dumper(\%hash_example);

OUTPUT:

$VAR1 = {
          'expectedvalue2' => [
                                'expectedvalue2'
                              ],
          'expectedvalue1' => [
                                'expectedvalue1'
                              ],
          'expectedvalue3' => [
                                'expectedvalue3'
                              ]
        };

answered Jun 3, 2020 at 11:27

Adrian

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1 Comment

Imad BELHAUSS Over a year ago

My bad I made a mistake in the name of keys, it's corrected now. And I'm looking foy key => value not key => array, @simbabque answer did the trick thank you very much

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