title: Python 2.7 replacing all values in a pandas DF
body: <p>in a pandas dataframe: everything I try replaces the key,value pairs in the first column, but not in the first and second. Here is the code:</p>
  
  <pre><code>module_names = {442990: 'Thank You', 442896:'Depression', 442924:'Irritability', 442879:'Anxiety', 442985:'sleep', 442875:'Meds'}
  for key, value in module_names.iteritems():
      df['module'].replace(key,value,inplace=True)
  print df.head(15)
  for key, value in module_names.iteritems():
      df['inResponseTo'].replace(key,value,inplace=True)
  print df.head(15)
  </code></pre>
  
  <p>And the output:</p>
  
  <pre><code>        module inResponseTo botNickname  botID result  \
  1      Thank You       442896   Web-Ducky  36931      4   
  3     Depression       442924   Web-Ducky  36931      4   
  5   Irritability       442879   Web-Ducky  36931      3   
  7        Anxiety       442985   Web-Ducky  36931      4   
  9          sleep       442875   Web-Ducky  36931    yes   
  11          Meds       442875   Web-Ducky  36931    NaN   
  13          Meds       442864   Web-Ducky  36931    NaN   
  19     Thank You       442896       Ducky  36931      3   
  </code></pre>
  
  <p>You can see I am not even trying to be terse, but I'm breaking it out to see if I can spot my error. Right now I'm stumped. TIA</p>