#!/usr/bin/perl -w use strict; my $base = 'ATCGGTAC'; print "base is $base\n"; my @pairs = SplitPairs($base); print "pairs are @pairs\n"; sub SplitPairs { my $base = shift; my $baselen = (length $base) - 2; my @pairs; for my $i (0 .. $baselen) { $pairs[$i] = substr $base, $i, 2; } return @pairs; } #### base is ATCGGTAC pairs are AT TC CG GG GT TA AC