title: Create an assoc array with equal keys and values from a regular array
body: <p>I have an array that looks like</p>
  
  <pre><code>$numbers = array('first', 'second', 'third');
  </code></pre>
  
  <p>I want to have a function that will take this array as input and return an array that would look like:</p>
  
  <pre><code>array(
  'first' =&gt; 'first',
  'second' =&gt; 'second',
  'third' =&gt; 'third'
  )
  </code></pre>
  
  <p>I wonder if it is possible to use <code>array_walk_recursive</code> or something similar...</p>