List.split() not cross platform?

Question

Recently I had some trouble writing code in Ubuntu and make it work in Windows.

Code on both platforms:

Output Ubuntu (that's what I want):

Output Windows:

As you can see, split on windows adds a '/' instead of splitting the list by '/'. Is the list.split() not cross platform?

Is there a simpler way to solve this other than checking for the OS in an if-statement? — Artur Müller Romanov, Dec 17 '18 at 08:34
What makes you think `list.split()` s the problem? What should it do in your opinion if there are no `/`s ion the string, but only `\`s? — glglgl, Dec 17 '18 at 08:43
please [Do not post image of code](https://meta.stackoverflow.com/a/285557/479251) — Pac0, Dec 17 '18 at 10:45

score 5 · Accepted Answer · answered Dec 17 '18 at 08:34

5

Use os.sep

Ex:

import os

importpath = __file__
print(importpath.split(os.sep))

answered Dec 17 '18 at 08:34

Rakesh

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Kind of right, but that doesn't include the case where a path under windows is separated by a `/`, which is valid too. – glglgl Dec 17 '18 at 08:35
This works in my case. Thank you. Could you elaborate how `os.sep` works exactly? How does it recognize by which characters it has to seperate? – Artur Müller Romanov Dec 17 '18 at 08:37
2

Have a look at the documentation of [`os.sep`](https://docs.python.org/3/library/os.html#os.sep). – Matthias Dec 17 '18 at 08:41
3

Note that it also reads "Note that knowing this is not sufficient to be able to parse or concatenate pathnames — use `os.path.split()` and `os.path.join()` — but it is occasionally useful." – glglgl Dec 17 '18 at 08:42

score 2 · Answer 2 · answered Dec 17 '18 at 08:42

A more "universal" way to do it is by using os.path.split(). This splits the path at the last separator. The first part must be treated iteratively or recursively.

Under Windows, think of splitting the drive letter as well.

Something like

drv, path = os.path.splitdrive(fullpath)
spl = []
while path:
    path, lastpart = os.path.split(path)
    spl.append(lastpart)
spl.append(drv) # as needed
spl.reverse()

should do it, but I don't have Windows at hand and cannot test it.

Serge Ballesta · Answer 3 · 2018-12-17T08:52:44.800

If you want to be super safe, you should use repeatedly os.path.split, or test for both os.sep and os.altsep as separator.

__file__ will always use os.sep, but when you get a path from other code or by direct input from a user, chances are that os.altsep ('/' on Windows) is used.

Example on Windows:

>>> path = os.path.join('c:\\a', 'c/d')
>>> print(path)
'c:\\a\\c/d'
>>> pathsep = re.compile(r'\\|/')
>>> pathsep.split(path)
['c:', 'a', 'b', 'c']

Alternatively:

 def safe_split(path):
    res = []
    while True:
        path, tail = os.path.split(path)
        if len(tail) == 0:
            break
        res.append(tail)
    res.append(path)           # do not forget the initial segment
    res.reverse()
    return res

and

>>> safe_split('c:\\a\\c/d')
['c:\\', 'a', 'c', 'd']

List.split() not cross platform?

3 Answers3