title: Scikit-Learn Vectorizer `max_features`
body: <p>How do I choose the number of the <code>max_features</code> parameter in <code>TfidfVectorizer</code> module? Should I use the maximum number of elements in the data?</p>
  
  <p>The <a href="http://scikit-learn.org/stable/modules/generated/sklearn.feature_extraction.text.TfidfVectorizer.html#sklearn.feature_extraction.text.TfidfVectorizer" rel="noreferrer">description</a> of the parameter does not give me a clear vision of how to choose the value for it:</p>
  
  <blockquote>
    <p>max_features : int or None, default=None</p>
    
    <p>If not None, build a vocabulary that only consider the top max_features ordered by term frequency across the corpus.
        This parameter is ignored if vocabulary is not None.</p>
  </blockquote>