title: Python lowercase error: 'list' object has no attribute 'str'
body: <p>I'm trying to convert all the values in a list to lowercase, using the following script:</p>
  
  <pre class="lang-py prettyprint-override"><code>def Data_Cleanse(Data_IMP):
      # Import Data_IMP file
      # Drop the EventTime, and EventID columns
  
      Data_Cleanse = Data_IMP.drop(columns = ["eventId","eventTime"])
  
      res = [sub.replace('.', ' - ') for sub in Data_Cleanse]
      res = [sub.replace("organization", "organisation") for sub in res]
  
      for i in res:
          res = res.str.lower[i]
  
      Data_Cleanse.columns = res
  
      return Data_Cleanse
  </code></pre>
  
  <p>The script works well until it gets to the for loop. When it gets to that point, I get the following error:</p>
  
  <blockquote>
    <p>AttributeError: 'list' object has no attribute 'str'</p>
  </blockquote>
  
  <p>The a sample of the res output file looks like this:</p>
  
  <blockquote>
    <p>['addrDate', 'birthCountry', 'birthDate', 'birthplace', 'branch',
    'brokerCode', 'businessEmail', 'businessPhoneNumber']</p>
  </blockquote>
  
  <p>Any suggestions on how to get around this error?</p>