my @l = (1, 2, 3, 0, 5, 6);
while (my $x = shift @l) { 
  print "$x ";
}

## OUTPUT ##

1 2 3 

##</code><code>##

my @l = (1, 2, 3, 0, 5, 6);
while (@l) { 
  my $x = shift @l;
  print "$x ";
}