title: Replace string key of PHP array
body: <p>I have an array in PHP which looks like that:</p>
  
  <pre><code>$test = array('3' =&gt; 5);
  </code></pre>
  
  <p>How could I replace the stringed array key 3?
  I tried:</p>
  
  <pre><code>$test['3'] = "New value"
  </code></pre>
  
  <p>but it don't work, it look like that after that:</p>
  
  <pre><code>array('3' =&gt; 5, 3 =&gt; "New value")
  </code></pre>
  
  <p>PHP version: 5.2.11</p>