So you say you have multiple values for certain keys.

key => value,value,value
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This directly translates to Perl:

my %hash = (
   key => [ value, value, value ],
   ...
);
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We call this a HoA, a hash of arrays as every value is another (anonymous) array-reference.

The creation of such a data structure is very easy with Perl as it has magic autovivification:

use Data::Dumper qw/Dumper/;

my %hash = ();

while( <DATA> ){
    chomp;

    my ($k,$v) = split /\s*:\s*/;

    push @{ $hash{ $k } } , $v
}

print Dumper( \%hash );
__DATA__
green : apple
yellow: banana
green : kiwi
red   : strawberry
green : mango
yellow: lemon
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That's it. Perl is great. update: see perlref and perldata of course.