in reply to Re: Re: input record separator help
in thread input record separator help

Anonymous Monk,
So my earlier assumption that you wanted to throw away non sequence lines was correct. I believe you can avoid an array all together. 
#!/usr/bin/perl
use strict;
use warnings;

my $file = $ARGV[0] || 'default';
open (DNA, '<', $file) or die "Unable to open $file for reading : $!";
my %seq;

while ( <DNA> ) {
    my $dna = <DNA>;
    my $pairs = "a2" x ((length $dna) / 2);
    $seq{$_}++ for unpack $pairs , $dna;
}
print "$_ : $seq{$_}\n" for keys %seq;

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Cheers - L~R

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Re: Re: Re: Re: input record separator help
by Anonymous Monk on Mar 15, 2004 at 15:00 UTC
    hi L~R, thankyou for your help, would you mind exaplaining to me exactly what the code does? e.g. the 'a2' and 'unpack' bits? many thanks
[reply]
      Anonymous Monk,
      You can check out the pack/unpack tutorial for more information, but here was my logic. 
      my $pairs = "a2" x ((length $dna)/2);
#  The x operator (perldoc perlop) repeats LHS string times the RHS


$seq{$_}++ for unpack $pairs, $dna;
#  Break string up into a list of 2 char strings
#  Increment the corresponding hash value by 1

      [download]
      Cheers - L~R
[reply]
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