Python encoding errors from comments containing Windows paths

Question

I want to include Windows paths in python script comments, without causing an encoding error.

If I include a Windows path in a comment, I will sometimes get an encoding error, e.g., "UnicodeDecodeError: 'utf-8' codec can't decode byte 0xa6 in position 4612: invalid start byte".
I found one "article" which indicated that including a Windows path in a comment can trigger a unicode error, https://programmersought.com/article/28013377080/.

On the other hand, sometimes I can include a Windows path in a comment, without triggering a unicode error. I don't understand why some Windows paths trigger errors, and other paths do not.

The following are a few examples of Windows paths that do, or do not cause encoding errors, as indicated below:

'''

OK      # E:\Apps\ParticlesByMarc\regularexpression_info_SAVE_aaa_.py
ERROR   # E:\Apps\UnitiesByMarc\regularexpression_info_SAVE_aaa_.py
OK      # E:\Apps\ UnitiesByMarc\regularexpression_info_SAVE_aaa_.py# File 
ERROR   # E:\ Apps\ UnitiesByMarc\xxx\regularexpression_info_SAVE_aaa_py
OK      # E:\ Apps\ UnitiesByMarc\ xxx\regularexpression_info_SAVE_aaa_py
OK      # File E:\ Apps\ UnitiesByMarc\x123x\regularexpression_info_SAVE_aaa_py

'''

I cannot figure out what makes two of those Windows path formats OK to be included in a comment, and the other four not OK to be included in a comment.

My questions:

Is there something I could do to format the comment so that I would not have to insert a space after each backslash?
If there are other limits on text that can be included in a comment, where can I find a list of those limits?
Where can I find the rules that identify and explain the reason for the limitations?

Any suggestions about how to find the answer would be very welcome.

Thanks, Marc

Read about special meaning of [Escape Sequences](https://docs.python.org/3/reference/lexical_analysis.html#string-and-bytes-literals) `\u`, `\U`, `\x` etc… — JosefZ, Jul 28 '21 at 18:12
Thank you so much for the reference. Because I have not learned any C yet, I do not understand some of it, perhaps most of it. But I get the impression that the best work around is for me to replace Windows backslashes with forward slashes when I put Windows paths in comments. Beyond that, it's a little over my head. But now I know that it's something I have to learn. So, thank you. — Marc B. Hankin, Jul 29 '21 at 16:15
You can use a _raw string_ (explained in the same link) `r'''E:\Apps\UnitiesByMarc\regularexpression_info_SAVE_aaa_.py'''`. — JosefZ, Jul 29 '21 at 18:49
Thank you again. That's a great solution, but my goal is to include Windows paths in multiline triple quoted comments. I get an error message if, for example, I make a comment like this one: """ Hello [new line character] r'''E:\Apps\UnitiesByMarc\regularexpression_info_SAVE_aaa_.py''' [new line character] """ — Marc B. Hankin, Jul 30 '21 at 19:37

score 1 · Accepted Answer · answered Jul 30 '21 at 20:46

A triple quoted string isn't a comment; it's a string which could become a Docstring:

A docstring is a string literal that occurs as the first statement in a module, function, class, or method definition. Such a docstring becomes the __doc__ special attribute of that object.

Example:

def somefunc(somepar):
  r'''
This is a docstring

  E:\Apps\ParticlesByMarc\regularexpression_info_SAVE_aaa_.py
  E:\Apps\UnitiesByMarc\regularexpression_info_SAVE_aaa_.py
# E:\Apps\UnitiesByMarc\regularexpression_info_SAVE_aaa_.py # File 
# E:\Apps\UnitiesByMarc\xxx\regularexpression_info_SAVE_aaa_py
  E:\Apps\UnitiesByMarc\xxx\regularexpression_info_SAVE_aaa_py
# File E:\Apps\UnitiesByMarc\x123x\regularexpression_info_SAVE_aaa_py

  '''
  print('supplied:', somepar, end='\n\n')
  '''
This isn't recognized as a docstring (i.e. not assigned to __doc__)
  '''


somefunc('par')
help(somefunc)

Result: .\SO\68553726.py

supplied: par

Help on function somefunc in module __main__:

somefunc(somepar)
    This is a docstring

      E:\Apps\ParticlesByMarc\regularexpression_info_SAVE_aaa_.py
      E:\Apps\UnitiesByMarc\regularexpression_info_SAVE_aaa_.py
    # E:\Apps\UnitiesByMarc\regularexpression_info_SAVE_aaa_.py # File
    # E:\Apps\UnitiesByMarc\xxx\regularexpression_info_SAVE_aaa_py
      E:\Apps\UnitiesByMarc\xxx\regularexpression_info_SAVE_aaa_py
    # File E:\Apps\UnitiesByMarc\x123x\regularexpression_info_SAVE_aaa_py

Dear JosefZ, I can't thank you enough. I have spent days trying to figure out what the problem was, and I obviously did not understand solutions that probably should have been obvious. Thank you for your kindness in showing me the solution. — Marc B. Hankin, Aug 01 '21 at 00:50
Dear JosefZ, I need to really study the Docstring material you kindly brought to my attention. But I couldn't resist ---> fyi, See Guido's tweet at https://twitter.com/gvanrossum/status/112670605505077248?ref_src=twsrc%5Etfw%7Ctwcamp%5Etweetembed%7Ctwterm%5E112670605505077248%7Ctwgr%5E%7Ctwcon%5Es1_&ref_url=https%3A%2F%2Fsgillies.net%2F2017%2F05%2F30%2Fpython-multi-line-comments-and-triple-quoted-strings.html — Marc B. Hankin, Aug 02 '21 at 01:50
Nor am I. There's no reason for you to apologize. You are wonderful. The help you gave me was invaluable and I've been trying to figure this out for years. I can't thank you enough. The spunky aspect of my character impelled me to bring Guido's statement to your attention because I thought you'd to know about it. I wish I could reciprocate for all the help you gave me. Marc — Marc B. Hankin, Aug 04 '21 at 17:11

Python encoding errors from comments containing Windows paths

1 Answers1