For unique values you probably want to use a hash instead of an array, something like this: 

while ( <FILE> ) {
    my ( $key, $value ) = split;

    $hash{ $key }{ $value } = ();
}
print Dumper \%hash;

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In reply to Re: assigning arrays as values to keys of hash by jwkrahn
in thread assigning arrays as values to keys of hash by pearllearner315

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