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Re: Conditional Sorting

by jdporter (Canon)
on May 11, 2007 at 05:31 UTC ( #614816=note: print w/ replies, xml ) Need Help??


in reply to Conditional Sorting

It appears that @arr are the nodes in a graph, and %hash are the weights of all the edges in the graph. (It's undirected, and fully connected.) So now you want to sort the nodes — but by what, exactly, is not clear. With the information given, I would surmise that the values for each node come from the weights of all its edges. If so, then the following:

use strict; use warnings; my @arr = ('foo','bar','qux','foo1','bar1','qux1'); my %hash = ( '4-5' => '0.750', '0-4' => '0.167', '0-2' => '0.600', '2-3' => '0.200', '2-4' => '0.300', '0-3' => '0.300', '2-5' => '0.400', '1-2' => '0.550', '1-5' => '0.273', '3-4' => '0.300', '1-4' => '0.182', '0-1' => '0.917', '3-5' => '0.400', '0-5' => '0.250', '1-3' => '0.300' ); my @nodew; for ( keys %hash ) { my $v = $hash{$_}; $nodew[$_] += $v for /(\d+)/g; } my @sorted_node_indices = sort { $nodew[$a] <=> $nodew[$b] } 0 .. $#nodew; my @arr_sorted = @arr[ @sorted_node_indices ];

Update: I see, you want, for each node, the list of its neighbor nodes sorted by edge weight.

use strict; use warnings; my @arr = ('foo','bar','qux','foo1','bar1','qux1'); my %hash = ( '4-5' => '0.750', '0-4' => '0.167', '0-2' => '0.600', '2-3' => '0.200', '2-4' => '0.300', '0-3' => '0.300', '2-5' => '0.400', '1-2' => '0.550', '1-5' => '0.273', '3-4' => '0.300', '1-4' => '0.182', '0-1' => '0.917', '3-5' => '0.400', '0-5' => '0.250', '1-3' => '0.300' ); my %edgew; for ( keys %hash ) { my( $from, $to ) = @arr[ /(\d+)/g ]; $edgew{$from}{$to} = $edgew{$to}{$from} = $hash{$_}; } for my $from ( sort keys %edgew ) { print "$from:\n"; print "\t$_ : $edgew{$from}{$_}\n" for sort { $edgew{$from}{$a} <=> $edgew{$from}{$b} } keys %{ $edgew{$from} }; }
A word spoken in Mind will reach its own level, in the objective world, by its own weight


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