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

my $string = "00021";
$string=~ s/^0*//;  # remove leading zero'es
print "$string\n";  # prints: 21

$string = "00021";
$string += 0;       # converts string to a numeric value
print "$string\n";  # prints: 21

$string = "00021scores";
#$string += 0;       # Warning: Argument "00021scores" isn't numeric in addition (+)
print "$string\n";  # prints: 21

$string = "0 but true";
$string += 33;      # Ha! A Perl special case! no warning!
print "$string\n";  # prints: 33

$string = "0E0";    # "better" way for a "logically true but zero value"
$string += 33;      # 
print "$string\n";  # prints: 33


my $nothing;
#print "$nothing\n"; # Use of uninitialized value $nothing in concatenation (.) or string
$nothing //= '';     # set $nothing to '' if it was undefined, else no operation.
print "$nothing\n";  # orint is ok, now..

my $nothing2;
$nothing2 = '' if !defined $nothing2; # pre Perl 5.10
print "$nothing2\n";