Re^2: Most elegant way to dispose of duplicates using map

[rashley]

Perfect, this is exactly what I was looking for. Thanks!

[rashley]

Just for the sake of intelectual growth, how could one tweak this to eliminate duplicates of id/versions pairs, instead of just id?

[johngg]

You just need to make a key for the %seen hash that is your id and version joined together in some way. Here I join them with a colon

use strict;
use warnings;

use Data::Dumper;

my @partTuples =
   (
      q{abc,1.1,apple},    # 1st element
      q{def,3.6,orange},   # no dups. so OK
      q{abc,1.5,pear},     # OK id only dup.
      q{abc,1.1,kiwi},     # dup. id and version
      q{ghi,1.2,peach},    # no dups. so OK
      q{xyz,1.1,plum},     # OK version only dup.
   );

my %seen = ();
my @uniquePTs =
   grep {! $seen{join q{:}, $_->{id}, $_->{version}} ++}
   map
   {
      {
         id             => $_->[0],
         version        => $_->[1],
         classification => $_->[2]
      }
   }
   map
   {
      [split m{,}]
   }
   @partTuples;

print Dumper(\@uniquePTs);

The output is

$VAR1 = [
          {
            'version' => '1.1',
            'classification' => 'apple',
            'id' => 'abc'
          },
          {
            'version' => '3.6',
            'classification' => 'orange',
            'id' => 'def'
          },
          {
            'version' => '1.5',
            'classification' => 'pear',
            'id' => 'abc'
          },
          {
            'version' => '1.2',
            'classification' => 'peach',
            'id' => 'ghi'
          },
          {
            'version' => '1.1',
            'classification' => 'plum',
            'id' => 'xyz'
          }
        ];

Cheers,

JohnGG

[exussum0]

I'd suggest using a very careful delimiter if you want to take a key and serialize it in this manner. if for instance, you used a comma, you have a key value pair of "1,2" and "3" and another of "1" and "2,3", they may evaluate the same.

[rashley]

I really need to crack the magic map/grep code.

I see what you're doing, and I think a colon will work for the data I'm dealing with, but if I understand this, I'll need to change the way I'm putting my original @partTuples together. This:

    @partTuples = map { my @t = split(','); 
                        {id=>$t[0],
                         version=>$t[1],
                         classification=>$t[2]} 
                      } @partTuples;

Isn't working, since we're doing the mapping later on, but I'm not sure what you're code is expecting.

Thanks for all the help.