title: map multiple columns by a single dictionary in pandas
body: <p>I have a DataFrame with a multiple columns with 'yes' and 'no' strings. I want all of them to convert to a boolian dtype. To map one column, I would use</p>
  
  <pre><code>dict_map_yn_bool={'yes':True, 'no':False}
  df['nearby_subway_station'].map(dict_map_yn_bool)
  </code></pre>
  
  <p>This would do the job for the one column. how can I replace multiple columns with single line of code? </p>