Automating Comparison of Word Documents Using Python

I created a more versatile version of this with path and file checks, if someone wants it...

#!/usr/bin/python3
# This uses win32com to automate the comparison of two Microsoft Word files.
# Make sure to have win32com installed for your environment and python version:
# https://github.com/mhammond/pywin32/releases
# Modified by 'pai' on basis of https://stackoverflow.com/questions/47212459/automating-comparison-of-word-documents-using-python

from os import getcwd, path
from sys import argv, exit
from win32com import client

def die(message):
    print (message)
    exit(1)

def cmp(original_file, modified_file):
  dir = getcwd() + '\\'
  print('Working...')

  # some file checks
  if not path.exists(dir+original_file):
    die('Original file does not exist')
  if not path.exists(dir+modified_file):
    die('Modified file does not exist')
  cmp_file = dir + original_file[:-5]+'_cmp_'+modified_file # use input filenames, but strip extension
  if path.exists(cmp_file):
    die('Comparison file already exists... aborting\nRemove or rename '+cmp_file)

  # actual Word automation
  app = client.gencache.EnsureDispatch("Word.Application")
  app.CompareDocuments(app.Documents.Open(dir + original_file), app.Documents.Open(dir + modified_file))
  app.ActiveDocument.ActiveWindow.View.Type = 3 # prevent that word opens itself
  app.ActiveDocument.SaveAs(cmp_file)

  print('Saved comparison as: '+cmp_file)
  app.Quit()

def main():
  if len(argv) != 3:
    die('Usage: wrd_cmp <original_file> <modified_file>')
  cmp(argv[1], argv[2])

if __name__ == '__main__':
  main()

The error is thrown because the arguments you pass in the function Application.CompareDocuments(), being written such as "Original.docx" and "Revised.docx", are not a Document object from the point of view of your python code.

You need to create these objects with the function Application.Documents.Open()

A code working for me is:

import win32com.client

path = "C:\ThePath\OfYourFolder\WithYourDocuments\\" 
# note the \\ at the end of the path name to prevent a SyntaxError

#Create the Application word
Application=win32com.client.gencache.EnsureDispatch("Word.Application")

# Compare documents
Application.CompareDocuments(Application.Documents.Open(path + "Original.docx"),
                             Application.Documents.Open(path + "Revised.docx"))

# Save the comparison document as "Comparison.docx"
Application.ActiveDocument.SaveAs (FileName = path + "Comparison.docx")
# Don't forget to quit your Application
Application.Quit()

The you have your Comparison.docx you can open to check.

Let me know if it works for you.

Ben. T's answer works. I would include:

Application.ActiveDocument.ActiveWindow.View.Type = 3

before saving if you like viewing the document in Print Layout. Otherwise the saved Comparison.docx opens as Web Layout by default (Type = 6).