title: Assign value from [0], [1], ... to Key
body: <p>I have this array:</p>
  
  <pre><code>array(2) {
    [0]=&gt;
    float(273)
    [1]=&gt;
    float(376)
  }
  </code></pre>
  
  <p>i tried to <code>$IDs = array_flip($params);</code>, but the var_dump of <code>$IDs</code> is <code>NULL</code></p>
  
  <p>The Reason is to filter a huge List of Items with this IDs.</p>