#!/usr/bin/perl --

use strict;
use warnings;

my $in = [ one => 1, two => 2, two => '2.003' ];
my $ou = {};
for( my $ix = 0; $ix < $#$in; $ix += 2){
    push @{ $ou->{ $in->[$ix] } }, $in->[$ix+1];
}

use Data::Dumper;
print Data::Dumper->new([ $in, $ou ] )->Indent(1)->Dump;

__END__
$VAR1 = [
  'one',
  1,
  'two',
  2,
  'two',
  '2.003'
];
$VAR2 = {
  'one' => [
    1
  ],
  'two' => [
    2,
    '2.003'
  ]
};
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