title: Convert excel file with timestamp to python date and time
body: <p>How can I convert a large .xlsx file which contains a lot of timestamps (i.e. 1537892885364) into date and time ( in python and then save it as a new .xlsx file?</p>
  
  <p>I am new to python, and I tried lots of ways to achieve this today, but I did not find a solution.</p>
  
  <p>Below is the code I used, but it gives me '[Errno 13] Permission denied'. I tried different ways which also gave problems.</p>
  
  <pre><code>from __future__ import absolute_import, division, print_function
  import os
  import pandas as pd
  
  def main(path, filename, absolute_path_organisation_structure):
      absolute_filepath = os.path.join(path,filename)
      #Relevant list formed with 4th, 5th and 6th columns
      df = pd.read_excel(absolute_filepath, header=None, parse_cols=[4,5,6])
      # Transform column 0 and 2 to datetime
      df[0] = pd.to_datetime(df[0])
      df[2] = pd.to_datetime(df[2])
      print(df)
  
  path = open(r'C:\\Users\\****\\data')
  MISfile  = 'filename.xlsx'
  main(path, MISfile,None)
  </code></pre>