[Tutor] How to programmatically EDIT a python file using an editorof my choice ?

[Dominique]

OK. 

With r before the path of the software, it works perfectly.
subprocess.Popen([r"C:\Program Files\Editra\Editra.exe", filename])
I saw that once but I don't remember and cannot find the reason for the use of r.

I'll try not to forget to test with and without r in case a file access doesn't
work.

Thanks a lot to both of you Sander and Alan for your help.

Dominique