title: Merge 2 arrays in random positions
body: <p>How would someone merge 2 arrays where <code>$_array_1</code> is scattered but <code>$_array_2</code> maintains its original order globally?</p>
  
  <p>I have 2 arrays</p>
  
  <pre><code>$_array_1 = array( a, b, c );
  
  $_array_2 = array( 1, 2, 3, 4, 5, 6 );
  
  $_merged_array = array( c, 1, a, 2, 3, 4, 5, b, 6 );
  </code></pre>
  
  <p>I know this must be possible but don't have a clue where to start. What is the most efficient method and cleanest?</p>