title: Creating n-grams word cloud using python
body: <p>I am trying to generate word cloud using bi-grams. I am able to generate the top 30 discriminative words but unable to display words together while plotting. My word cloud image still looks like a uni-gram cloud. I have used the following script and sci-kit learn packages.</p>
  
  <pre><code>def create_wordcloud(pipeline): 
  """
  Create word cloud with top 30 discriminative words for each category
  """
  
  class_labels = numpy.array(['Arts','Music','News','Politics','Science','Sports','Technology'])
  
  feature_names =pipeline.named_steps['vectorizer'].get_feature_names() 
  word_text=[]
  
  for i, class_label in enumerate(class_labels):
      top30 = numpy.argsort(pipeline.named_steps['clf'].coef_[i])[-30:]
  
      print("%s: %s" % (class_label," ".join(feature_names[j]+"," for j in top30)))
  
      for j in top30:
          word_text.append(feature_names[j])
      #print(word_text)
      wordcloud1 = WordCloud(width = 800, height = 500, margin=10,random_state=3, collocations=True).generate(' '.join(word_text))
  
      # Save word cloud as .png file
      # Image files are saved to the folder "classification_model" 
      wordcloud1.to_file(class_label+"_wordcloud.png")
  
      # Plot wordcloud on console
      plt.figure(figsize=(15,8))
      plt.imshow(wordcloud1, interpolation="bilinear")
      plt.axis("off")
      plt.show()
      word_text=[]
  </code></pre>
  
  <p>This is my pipeline code</p>
  
  <pre><code>pipeline = Pipeline([
  
  # SVM using TfidfVectorizer
  ('vectorizer', TfidfVectorizer(max_features = 25000, ngram_range=(2, 2),sublinear_tf=True, max_df=0.95, min_df=2,stop_words=stop_words1)),
  ('clf',       LinearSVC(loss='squared_hinge', penalty='l2', dual=False, tol=1e-3))
  ])
  </code></pre>
  
  <p>These are some of the features I got  for the category "Arts"</p>
  
  <pre><code>Arts: cosmetics businesspeople, television personality, reality television, television presenters, actors london, film producers, actresses television, indian film, set index, actresses actresses, television actors, century actors, births actors, television series, century actresses, actors television, stand comedian, television personalities, television actresses, comedian actor, stand comedians, film actresses, film actors, film directors
  </code></pre>