Hi,

I want the contents of column 2 (when NAN/0)in file1.txt to be replaced by the content of column1:

file1.txt:

file for parsing
mnot    NAN
PU1    0
PU2    ets
munt    tsu
PU3    ttsm
munt2    0

Required output:

file for parsing
mnot     mnot
PU1    PU1
PU2    ets
munt    tsu
PU3    ttsm    
munt2    munt2

my code is not giving the right output:

#!usr/bin/perl
use warnings;
use strict;
use diagnostics;

open(IN, "<", "file1.txt") or die "Can't open file for reading:$!";

open(OUT, ">", "outfile.txt") or die "Can't open file for writing:$!";

my $header = <IN>;
print OUT $header;


while (<IN>){
chomp;
my @sections = split(/\t/);
$sections[1] = 0; # Error: initialization in wrong place
$sections[2] = 0; # Error: s.o., also array index in perl starts at 0!

 if (($sections[2] eq 'NAN') || ($sections[2] == 0)) { # Error: always true because you set $sections[2] = 0!
     # Error: the first and second column would be in $section[0], $section[1]
    #print OUT $sections[1], "\t", $sections[1], "\n"; 
    print OUT "$sections[1]\n"; # Error: you commented away the correctly formatted output (minus wrong array index)
    }    
    else {
    #print OUT $sections[1], "\t", $sections[2], "\n";
            # Error: s.o.
    print OUT "$sections[2]\n"; # Error: you commented out the correctly formatted output (minus wrong array index)
    }
  }

Please help!