title: Counting number of zeros per row by Pandas DataFrame?
body: <p>Given a DataFrame I would like to compute number of zeros per each row. How can I compute it with Pandas?</p>
  
  <p>This is presently what I ve done, this returns indices of zeros</p>
  
  <pre><code>def is_blank(x):
      return x == 0 
  
  indexer = train_df.applymap(is_blank)
  </code></pre>