title: remove special character in scrapy python
body: <p>I try to remove the special characters between the following text:</p>
  
  <pre><code>sample_sample_sample_2.18.14
  </code></pre>
  
  <p>I tried following patterns for remove those special characters: </p>
  
  <pre><code>item['xxxx'] = item['aaaa'].replace('_' '' ,'-' '')
  </code></pre>
  
  <p>I can able to remove the <code>_</code> characters alone.</p>
  
  <p>I try to remove all characters like: <code>.   ,   _   ,  -  ,  (  ,  )</code>.</p>