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calculating number combinations in perl

Posted on 2009-07-07
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Last Modified: 2012-05-07
I have a small problem. I am working on a probability solution.

I have quasi-randomly generated data sets, from the value of 1 to 999. These values are the end result of another mathematical process.

The data comes out in groups of seven, eight and ten.

We have a mid range of 501-550.

If I could get help on the seven group problem, Im sure I could find my way with the other two groups when I can see the code structure.

I need to build a database (which could be a text file if it is big enough) of all possible value combinations, so out of the 50 numbers, from 501 to 550.

So the first possible combination would be
501,502,503,504,505,506,507

Then the next possible combination would be
501,502,503,504,505,506,508

And the combinations would tick up one at a time until
544,545,546,547,548,549,550, which would be the final one.

I expect about 10 million results.

I need each individual result output to a text file / word pad one line at a time, delineated by a comma.

Could you tell me perl code which would do this ?

Thankyou very much
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Question by:Europa MacDonald
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5 Comments
 
LVL 39

Expert Comment

by:Adam314
ID: 24799045

use Math::Combinatorics;
 
 
my $combin = Math::Combinatorics->new(count => 7, data => [501..550]);
 
while(my @combo = $combin->next_combination){
	print join(',', @combo)."\n";
}

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Author Comment

by:Europa MacDonald
ID: 24799053
thankyou Adam

would this print out to a text file ?
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LVL 13

Accepted Solution

by:
Carl Bohman earned 500 total points
ID: 24799133
If you don't have Math::Combinatorics installed and can't install it for some reason, here's a code version.

For either my solution or Adam's, just redirect the output to a text file using the greater than symbol:
scriptname.pl > filename.txt
my $count = 3;
my $low = 501;
my $high = 550;
 
sub cmb
{
  my ($rem, $used, $text, $min) = @_;
  $rem--;
 
  for my $n ($min..($high - $rem))
  {
    next if $used->{$n};
    if ($rem)
    {
      $used->{$n} = 1;
      cmb($rem, $used, "$text$n,", $n + 1);
      $used->{$n} = 0;
    } else
    {
      print "$text$n\n"
    };
  }
}
 
my %h;
cmb($count, \%h, "", $low);

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0
 

Author Comment

by:Europa MacDonald
ID: 24799168
thankyou

where would I put

scriptname.pl > filename.txt

?

0
 

Author Closing Comment

by:Europa MacDonald
ID: 31600854
worked out the file thing myself
thankyou very much
0

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