title: How to loop over an Array of Arrays as reference?
body: <p>The below code works if <code>$a</code> is an Array of Arrays, but I need <code>$a</code> to be an reference to the Array of Arrays.</p>
  
  <p><strong>Question</strong></p>
  
  <p>How do I iterate through <code>$a</code>?</p>
  
  <pre><code>#!/usr/bin/perl
  
  use warnings;
  use strict;
  use Data::Dumper;
  
  my @AoA = ( ['aaa','hdr','500'],
              ['bbb','jid','424'],
              ['ccc','rde','402'],
              );
  
  my $a = \@AoA;
  
  my $s = "bbb";
  my $d = "ddd";
  
  for my $i ( 0 .. $#a ) {
      for my $j ( 0 .. $#{ $a[$i] } ) {
          if ($a[$i][$j] eq $s) {
              $a[$i][$j] = $d;
              last;
          }
      }
  }
  
  print Dumper $a;
  </code></pre>