title: How to check if a string contains a specific text
body: <pre><code>&lt;?php
  $a = '';
  
  if($a exist 'some text')
      echo 'text';
  ?&gt;
  </code></pre>
  <p>Suppose I have the code above, how to write the statement <code>if($a exist 'some text')</code>?</p>