[Tutor] Regex for Filesystem path (Asad)

[Peter Otten]

Albert-Jan Roskam wrote:

> I was thinking it would also be possible to do (in Windows):
> import os.path
> os.path.sep = '/'
> os.path.normpath('c:\\beeh/foo\\bar/baz')
> 
> But alas, this still creates normalized windows-style paths.

If your input data has only forward slashes you can keep it that way with 
posixpath, i. e.

>>> import posixpath
>>> posixpath.join("foo", "bar")
'foo/bar'

should produce the same result on windows.
posixpath.normpath() cannot replace backward with forward slashes because 
the backslash is an ordinary character on Linux et. al.

Fun fact: scripts written with Windows in mind sometimes work on Linux, with 
the output going to unexpected places:

$ python3
Python 3.4.3 (default, Nov 28 2017, 16:41:13) 
[GCC 4.8.4] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> with open("c:\\foo\\bar.txt", "w") as f: print("hi", file=f)
... 
>>> 
$ ls
c:\foo\bar.txt