title: How to abstract bigram topics instead of unigrams using Latent Dirichlet Allocation (LDA) in python- gensim?
body: <h1>LDA Original Output</h1>
  
  <ul>
  <li><p>Uni-grams </p>
  
  <ul>
  <li><p>topic1 -scuba,water,vapor,diving</p></li>
  <li><p>topic2 -dioxide,plants,green,carbon</p></li>
  </ul></li>
  </ul>
  
  <h1>Required Output</h1>
  
  <ul>
  <li><p>Bi-gram topics</p>
  
  <ul>
  <li><p>topic1 -scuba diving,water vapor</p></li>
  <li><p>topic2 -green plants,carbon dioxide</p></li>
  </ul></li>
  </ul>
  
  <p>Any idea?</p>