Then just peek back. 

use strict;
use warnings;

my @alphas = split ' ', 'A G C T G G G G A C T T T A G C';
my @nums   = split ' ', '34 23 43 45 34 43 45 7 45 43 12 34 32 56 43 6
+7';

my @keep = grep {  $_ < 1
                || $nums[$_] >= 10
                || $alphas[$_-1] ne $alphas[$_-0]
                }
           0..$#nums;

print( join( ' ', @alphas[ @keep ] ), "\n" );
print( join( ' ', @nums  [ @keep ] ), "\n" );

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In reply to Re^3: finding position by ikegami
in thread finding position by heidi

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