title: php: How to get the second-to-last element of an array?
body: <p>There is an array, the count of the element is unknown,like this:</p>
  
  <pre><code>$arr=['a','m','q','y',....'b','f','n','s'];
  </code></pre>
  
  <p>How to get the second-to-last element in <code>PHP</code>?</p>