title: How to change dataframe column names without changing the values?
body: <p>I have a bunch of CSV files which are read as dataframes. For each dataframe, I want to change some column names, if a specific column exists in a dataframe:</p>
  
  <p>column_name_update_map = {'aa': 'xx'; 'bb': 'yy'}</p>
  
  <p>In such a map, if 'aa' or 'bb' exists in a dataframe, I want to change the aa to xx, and 'bb' to 'yy'. No values should be changed.</p>
  
  <pre><code>  for file in files:
          print('Current file: ', file)
          df = pd.read_csv(file, sep='\t')
          df = df.replace(np.nan, '', regex=True)
          for index, row in df.iterrows(): 
  
             pass
  </code></pre>
  
  <p>I don't think I should use the inner loop, but if I have to do, what's the right way to change the column name only? </p>