title: Creating a new column depending on the equality of two other columns
body: <p>l want to compare the values of two columns where I create a new column <code>bin_crnn</code>. I want 1 if they are equals or 0 if not.</p>
  
  <pre><code># coding: utf-8
  import pandas as pd
  
  df = pd.read_csv('file.csv',sep=',')
  
  if df['crnn_pred']==df['manual_raw_value']:
      df['bin_crnn']=1
  else:
      df['bin_crnn']=0
  </code></pre>
  
  <p>l got the following error</p>
  
  <pre><code>    if df['crnn_pred']==df['manual_raw_value']:
    File "/home/ahmed/anaconda3/envs/cv/lib/python2.7/site-packages/pandas/core/generic.py", line 917, in __nonzero__
      .format(self.__class__.__name__))
  ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().
  </code></pre>