Sorting large sets of geometric coordinatesby Anonymous Monk
|on Apr 19, 2006 at 20:29 UTC||Need Help??|
Anonymous Monk has asked for the
wisdom of the Perl Monks concerning the following question:
I could use some guidance on the best way to tackle a somewhat complex sorting problem I need to work though. I will try to keep this as generic as possible.
I have to grab 4 numbers from every line in a file. Each line is formatted in a very predictable pattern. Say I name each number like so:-
NOTE: Many of the $row_lx values will be the same.
Here is a nice, neat, golden output. Imagine all of the following lines were originally completely out of order:-
((1.0 0.1) (99.0 0.2))
Notice that the second number (highest priority), $row_ly, always increases, and sometimes it is repeated. When it does repeat, always print the $row_lx numbers in order (second priority).
I hope this is clear enough. Any recommendations? I think I need a hash with two primary key values, but I don't know how to sort the hash to produce the above output.