title: Python regex removing non alpha numeric characters from string except brackets
body: <p>I have the following regex , which remove all no alpha numeric characters from a string text</p>
  
  <pre><code>re.sub(r'[^a-zA-Z0-9]',' ', text)
  </code></pre>
  
  <p>How can I modify this expression to include the characters '[' and ']' in the string text ?</p>