my @match_A = split /\t/, $line;
push @list_of_headers, @match_A[4..$#match_A];
[download]

@list_of_headers= @match_A[4..$#match_A];
[download]

Your code (that, what you wanted) should be as easy as:

my @match_A = split /\t/, $line;
@list_of_headers= @match_A[4..$#match_A];
[download]

No need for a loop...

... provided @list_of_headers was empty beforehand! Otherwise use

push @list_of_headers, @match_A[4..$#match_A];
[download]

-- Hofmator

Code written by Hofmator and posted on PerlMonks is public domain. It is provided as is with no warranties, express or implied, of any kind. Posted code may not have been tested. Use of posted code is at your own risk.

It looks like you're trying to scan columns 4 though the end of the line for a particular pattern for each line.

Perhaps this sorta golf-like snippet will help.

#!/usr/bin/perl

use strict;
use warnings;

my $pattern = qr/[45fg]/; # Look for "4,5,f,g"

while(<DATA>) {
    chomp, 
    print "$_\n" 
        for grep { /$pattern/ }
            ((split /\t/)[3 .. s/\t(?!\n)/\t/g ]);
}

__DATA__
1   2   3   4   5   6   7   8   9   108 9   
a   b   c   d   e   f   g   h   i   j
[download]

Pax vobiscum,
-v.

Please see How do I post a question effectively?. Your code looks good so far.

What should be looked for in the for loop?

--shmem

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

bit picky, but shouldn't that be

for (4..$#match_A) {
[download]

?

In scalar context, @array (or in your case, @match_A) evaluates to the number of elements in an array. That's not quite what you're looking for; you're looking for the highest index, which is @array - 1^*. But Perl gives you a way to get the index of the last element without doing math; $#array (or in your case, $#match_A) will tell you the index of the ultimate element in the array.

So, for( 4 .. $#match_A ) {....... will do the trick.

^*Note: @array - 1 will also be the index of the highest element, but that assumes you've left $[ alone, which you should. If you've messed with $[ you've committed an egregious foul.