Why did you use 
$#data ++

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The normal way to add a new member to an array is to use push: 

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

my @data;
while (my $line = <>) {
    if ($line =~ /^(.*) (\d+)$/) {
        push @data, $1;
    }
}

for my $d (@data) {
        print "$d\n";
}

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Update: When @data is empty, $#data ++ returns -1, but for some reason, and creates one empty element in the array (same as $#data = 0), so Perl doesn't die with 

Modification of non-creatable array value attempted, subscript -1

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as it does for 

my @data;
$data[-1] = 2;

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In the next iteration of the loop, $#data is 0 (and so is $#data ++), so the assignment overwrites the first assigned value.

لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ

In reply to Re: using while, first line was skipped by choroba
in thread using while, first line was skipped by rendus

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