title: How can I add class labels in python?
body: <p>I have gaussian data which is:</p>
  
  <pre><code>r1=np.random.multivariate_normal(mean1, cov1, 3000)
  r2=np.random.multivariate_normal(mean2, cov2, 3000)
  </code></pre>
  
  <p>Now I want to add class labels for these datas to train a classifier. 
  For r1, it is class1 and for r2, it is class2. How can I add the class labels?</p>