title: Exclude words that appears in a list from a string
body: <p>I have such list:</p>
  
  <pre><code>stopwords = ['a', 'and', 'is']
  </code></pre>
  
  <p>and such sentence:</p>
  
  <pre><code>sentence = 'A Mule is Eating and drinking.'
  </code></pre>
  
  <p>Expected output:</p>
  
  <pre><code>reduced = ['mule', 'eating', 'drinking']
  </code></pre>
  
  <p>I have so far:</p>
  
  <pre><code>reduced = filter(None, re.match(r'\W+', sentence.lower()))
  </code></pre>
  
  <p>Now how would you filter out the stopwords (Note the upper to lowercase conversion as well as ommitance of punctuation)?</p>