title: how to restrict special chars in REGEXP
body: <p>I am doing to validate textbox field. Here the below code i validated like it should contain chars and decimal numbers and spaces only allowed in regexp. But now i want to do like that it should restrict special chars. The below code allowed the special chars. Cany anyone help me to do this</p>
  
  <pre><code>  p = re.compile('[a-zA-z0-9_](\w+ ?)(?:([0-9])+([\,\.][0-9]+))?')
  </code></pre>
  
  <p>Thanks in advance</p>