in reply to What would be the easier way

Use a hash table with an array ref for each entry, doing something like push @{ $height{$input} }, $value; after parsing each line into $input and $value; leaving you with something like this:

%height = ( 'house' => [ string1, string2 ], 'table' => [ string3, string4 ] )
and @{$height{house}} would be all the values for house in an array