How can I start incrementing an index at 0?

raj8 has asked for the wisdom of the Perl Monks concerning the following question: ⭐ (arrays)

Hello Perl Monks, I am have been attempting to unpack columns and increment the output, however, the increment operator starts at 1. Here is an example output:

drive      0    
dirve      1
drive      2    
drive      3    

I am using this:

open(LIST,"list -l|");
    while(<LIST>) {
    ($drive) = unpack '@0 A3',$_;
          if(/Drive/) {
           $count++;
    }
system("list -delete -dr -index ${count}");
};

However, when it gets to 3 it says can't delete 4 because
the $i++ started at 1 instead of 0.
[download]

Any suggestions would help. thanks-- raj8

Originally posted as a Categorized Question.

Comment on How can I start incrementing an index at 0? Download Code

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Re: How can I start incrementing an index at 0?⭐ by Adam (Vicar) on Sep 02, 2000 at 05:33 UTC
First of all, the quick answer: declare $count = -1; somewhere earlier. Next the long answer. Your code is not good for a variety of reasons, most of which you learn from practice and experience, which if you hang out here you will gain quickly. Try this: `use strict; # always. my $drive; my $count = -1; open( LIST, "list -l\|" ) or die $!; while(<LIST>) { ($drive) = unpack '@0 A3',$_; ++$count if m/Drive/; system("list -delete -dr -index ${count}"); }` [download] This code can still made better, but that should get you off to a good start.	[reply] [d/l]

Replies are listed 'Best First'.

Re: How can I start incrementing an index at 0?⭐
by Adam (Vicar) on Sep 02, 2000 at 05:33 UTC

Next the long answer. Your code is not good for a variety of reasons, most of which you learn from practice and experience, which if you hang out here you will gain quickly. Try this:

use strict; # always.
my $drive;
my $count = -1;
open( LIST, "list -l|" ) or die $!;
while(<LIST>) 
{
    ($drive) = unpack '@0 A3',$_;
    ++$count if m/Drive/;
    system("list -delete -dr -index ${count}");
}
[download]

[reply]
[d/l]