Creating a Matrix in perl...: Perl, Matrix, Array

Creating a Matrix in perl...

I'm doing a computation and that will result in 3 variable (Document name, document value, document term frequency) The values of the computation is in 3 separate variable, so I was thinking of grouping the values into an array or hash so I can sort the result of the computation by the following rules.

The highest document value and the highest term frequency.

here is a sample data

doc1, 0.002, 1
doc2, 0.012, 2
doc3, 0.032, 1

the search Martrix should be like this

doc2, 0.012, 2
doc3, 0.032, 1
doc1, 0.002, 1

How can I create a matrix in perl? or an array of array?

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#!/usr/bin/perl my %docs; $docs{doc1} = { value => 0.002, freq => 1 }; $docs{doc2} = { value => 0.012, freq => 2 }; $docs{doc3} = { value => 0.032, freq => 1 }; print "Unsorted\n"; foreach my $doc (keys %docs) { print "$doc $docs{$doc}->{freq}\n"; } print "Sorted\n"; foreach my $doc (sort {$docs{$b}->{freq} <=> $docs{$a}->{freq}} keys %docs) { print "$doc $docs{$doc}->{freq}\n"; }

You can, it depends really on what you want. The <=> and cmp operators compare 2 values and return -1, 0 or 1. But you can write a sort function that makes it clearer.

So basically comparing the 1st column, if they are not equivalent, return the sort order just based on 1st column, but if they are equivalent, then return sort based on 2nd.

There may be an even more elegant solution to this, but this is how I would do it.

Keep in mind this is sorting on the fly. If you want to maintain a sorted datastructure with many items, you probably should sort them as you store them.

#!/usr/bin/perl
 
my %docs;
 
$docs{doc1} = { value => 0.002, freq => 1 };
$docs{doc2} = { value => 0.012, freq => 2 };
$docs{doc3} = { value => 0.032, freq => 1 };
$docs{doc4} = { value => 0.032, freq => 2 };
 
print "Unsorted\n";
foreach my $doc (keys %docs) {
   print "$doc $docs{$doc}->{value} $docs{$doc}->{freq}\n";
}
 
print "Sorted\n";
foreach my $doc (sort sort2desc keys %docs) {
   print "$doc $docs{$doc}->{value} $docs{$doc}->{freq}\n";
}
 
sub sort2desc {
   if($docs{$b}->{freq} > $docs{$a}->{freq}) {
      return 1;
   }
   elsif($docs{$b}->{freq} < $docs{$a}->{freq}) {
      return -1;
   }
   else {
      # 1st field equal, so sort by 2nd field
      return $docs{$b}->{value} <=> $docs{$a}->{value};
   }
}

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Creating a Matrix in perl...

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Perl

Matrix

Array

Perl Programming Language

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