I surely have learnt a lot in this thread. I still do not understand what the window size is good for. If you do all combinations within a window and then combine across all windows you get the same as if you were doing all combinations straight away. Or does a specific letter always have the same level within a window?

Anyways, putting all of the above together (and ignoring the window issue), you get the following code creating 864 combinations: 

use strict;
use warnings;
my %level = ( A=>3, T=>2, G=>2, C=>1 );
my $string = "ATATGCGCAT";
my $n = 1;
$n *= $level{$_} for( split '', $string );
print "Number of combinations: $n\n";
$string =~ s/(.)/$1."{".join(",",1..$level{$1})."}"/ge;
print "~$_\n" while(< $string >);

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In reply to Re: How can one get all possible combinations of a string without changing positions & using window size? by hdb
in thread How can one get all possible combinations of a string without changing positions & using window size? by supriyoch_2008

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