title: How to find out the differences of 2 arrays?
body: <p>I have 2 arrays : </p>
  
  <ol>
  <li>$valid_sku_array</li>
  <li>$qb_sku_array</li>
  </ol>
  
  <p>I want to <code>intersect</code> them, and print out the <code>bad</code> one (diff)</p>
  
  <p>Then I do this : </p>
  
  <pre><code>        // Case Sensitive
          $intersect_sku_array_s = array_intersect( $valid_sku_array, $qb_sku_array );
  
         dd($intersect_sku_array_s); ... array (size=17238) 
  </code></pre>
  
  <p>Then I also tried with the Case Insensitive by doing this : </p>
  
  <pre><code>    // Case Insensitive
      $intersect_sku_array_is = array_intersect(array_map('strtolower', $valid_sku_array), array_map('strtolower', $qb_sku_array ));
  
      dd($intersect_sku_array_is); ... array (size=18795)  
  </code></pre>
  
  <p>As you can see the diff of both array = 18795 - 17238 = 1557.
  I want to see what are they. Then I tried this : </p>
  
  <p><code>$diff = array_diff( $intersect_sku_array_is , $intersect_sku_array_s  );</code></p>
  
  <p>and when do <code>dd($diff);</code> I got <code>array (size=18795)</code></p>
  
  <p>I just couldn't figure it out how to get to print out those <strong>1557</strong>.</p>
  
  <p>Can someone please explain what is going on here ?</p>