It's difficult to explain in english that... I don't undertand what is really your problem. The code in Re: How can I count the number and kinds of letters at 1st, 2nd and 3rd positions of 3-letter words in a string? is not very nice but it is simple and I don't understand the aim of your corrections.

You said: I didn't write "use strict" at the beginning of the code intentionally. -- Don't do that! It's baaaad! use strict; is your best friend!

It seems you don't what to use an hash. Why ? $A1,$G1...$C3: 12 variables!!!

Finnaly, my script was probably not so simple and I propose another one, with one hash and keys like "A1" or "G3".

#!perl
use strict;
use warnings;

my $seq = "ATCGGCGCCTAT" ;
my %poscount;

my @trilet = $seq =~ /.../g;
#print join "\n",@trilet;

foreach my $let ('A','T','G','C') { #init
    $poscount{$let.'1'}=0;
    $poscount{$let.'2'}=0;
    $poscount{$let.'3'}=0;
}

foreach my $tri (@trilet) {
    print "processing '$tri'\n";
    my $let1 = substr $tri,0,1;
    $poscount{$let1.'1'}++;
    print $let1,"1++\t";
    my $let2 = substr $tri,1,1;
    $poscount{$let2.'2'}++;
    print $let2,"2++\t";
    my $let3 = substr $tri,2,1;
    $poscount{$let3.'3'}++;
    print $let3,"3++\n\n";
}

foreach my $pos (1,2,3) {
    foreach my $let ('A','T','G','C') {
        my $letpos = $let.$pos;
        print "$letpos=$poscount{$letpos}; "
    }
    print "\n";
}
__END__
processing 'ATC'
A1++    T2++    C3++

processing 'GGC'
G1++    G2++    C3++

processing 'GCC'
G1++    C2++    C3++

processing 'TAT'
T1++    A2++    T3++

A1=1; T1=1; G1=2; C1=0; 
A2=1; T2=1; G2=1; C2=1; 
A3=0; T3=1; G3=0; C3=3; 
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