title: Tensorflow vocabularyprocessor
body: <p>I am following the wildml blog on text classification using tensorflow. I am not able to understand the purpose of max_document_length in the code statement :</p>
  
  <pre><code>vocab_processor = learn.preprocessing.VocabularyProcessor(max_document_length)
  </code></pre>
  
  <p>Also how can i extract vocabulary from the vocab_processor</p>