cross-platform splitting of path in python

Question

I'd like something that has the same effect as this:

>>> path = "/foo/bar/baz/file" >>> path_split = path.rsplit('/')[1:] >>> path_split ['foo', 'bar', 'baz', 'file'] 

But that will work with Windows paths too. I know that there is an os.path.split() but that doesn't do what I want, and I didn't see anything that does.

Answer 1

Python 3.4 introduced a new module pathlib. pathlib.Path provides file system related methods, while pathlib.PurePath operates completely independent of the file system:

>>> from pathlib import PurePath >>> path = "/foo/bar/baz/file" >>> path_split = PurePath(path).parts >>> path_split ('\\', 'foo', 'bar', 'baz', 'file') 

You can use PosixPath and WindowsPath explicitly when desired:

>>> from pathlib import PureWindowsPath, PurePosixPath >>> PureWindowsPath(path).parts ('\\', 'foo', 'bar', 'baz', 'file') >>> PurePosixPath(path).parts ('/', 'foo', 'bar', 'baz', 'file') 

And of course, it works with Windows paths as well:

>>> wpath = r"C:\foo\bar\baz\file" >>> PurePath(wpath).parts ('C:\\', 'foo', 'bar', 'baz', 'file') >>> PureWindowsPath(wpath).parts ('C:\\', 'foo', 'bar', 'baz', 'file') >>> PurePosixPath(wpath).parts ('C:\\foo\\bar\\baz\\file',) >>> >>> wpath = r"C:\foo/bar/baz/file" >>> PurePath(wpath).parts ('C:\\', 'foo', 'bar', 'baz', 'file') >>> PureWindowsPath(wpath).parts ('C:\\', 'foo', 'bar', 'baz', 'file') >>> PurePosixPath(wpath).parts ('C:\\foo', 'bar', 'baz', 'file') 

Huzzah for Python devs constantly improving the language!

Answer 2

The OP specified "will work with Windows paths too". There are a few wrinkles with Windows paths.

Firstly, Windows has the concept of multiple drives, each with its own current working directory, and 'c:foo' and 'c:\\foo' are often not the same. Consequently it is a very good idea to separate out any drive designator first, using os.path.splitdrive(). Then reassembling the path (if required) can be done correctly by drive + os.path.join(*other_pieces)

Secondly, Windows paths can contain slashes or backslashes or a mixture. Consequently, using os.sep when parsing an unnormalised path is not useful.

More generally:

The results produced for 'foo' and 'foo/' should not be identical.

The loop termination condition seems to be best expressed as "os.path.split() treated its input as unsplittable".

Here's a suggested solution, with tests, including a comparison with @Spacedman's solution

import os.path  def os_path_split_asunder(path, debug=False):     parts = []     while True:         newpath, tail = os.path.split(path)         if debug: print repr(path), (newpath, tail)         if newpath == path:             assert not tail             if path: parts.append(path)             break         parts.append(tail)         path = newpath     parts.reverse()     return parts  def spacedman_parts(path):     components = []      while True:         (path,tail) = os.path.split(path)         if not tail:             return components         components.insert(0,tail)  if __name__ == "__main__":     tests = [         '',         'foo',         'foo/',         'foo\\',         '/foo',         '\\foo',         'foo/bar',         '/',         'c:',         'c:/',         'c:foo',         'c:/foo',         'c:/users/john/foo.txt',         '/users/john/foo.txt',         'foo/bar/baz/loop',         'foo/bar/baz/',         '//hostname/foo/bar.txt',         ]     for i, test in enumerate(tests):         print "\nTest %d: %r" % (i, test)         drive, path = os.path.splitdrive(test)         print 'drive, path', repr(drive), repr(path)         a = os_path_split_asunder(path)         b = spacedman_parts(path)         print "a ... %r" % a         print "b ... %r" % b         print a == b 

and here's the output (Python 2.7.1, Windows 7 Pro):

Test 0: '' drive, path '' '' a ... [] b ... [] True  Test 1: 'foo' drive, path '' 'foo' a ... ['foo'] b ... ['foo'] True  Test 2: 'foo/' drive, path '' 'foo/' a ... ['foo', ''] b ... [] False  Test 3: 'foo\\' drive, path '' 'foo\\' a ... ['foo', ''] b ... [] False  Test 4: '/foo' drive, path '' '/foo' a ... ['/', 'foo'] b ... ['foo'] False  Test 5: '\\foo' drive, path '' '\\foo' a ... ['\\', 'foo'] b ... ['foo'] False  Test 6: 'foo/bar' drive, path '' 'foo/bar' a ... ['foo', 'bar'] b ... ['foo', 'bar'] True  Test 7: '/' drive, path '' '/' a ... ['/'] b ... [] False  Test 8: 'c:' drive, path 'c:' '' a ... [] b ... [] True  Test 9: 'c:/' drive, path 'c:' '/' a ... ['/'] b ... [] False  Test 10: 'c:foo' drive, path 'c:' 'foo' a ... ['foo'] b ... ['foo'] True  Test 11: 'c:/foo' drive, path 'c:' '/foo' a ... ['/', 'foo'] b ... ['foo'] False  Test 12: 'c:/users/john/foo.txt' drive, path 'c:' '/users/john/foo.txt' a ... ['/', 'users', 'john', 'foo.txt'] b ... ['users', 'john', 'foo.txt'] False  Test 13: '/users/john/foo.txt' drive, path '' '/users/john/foo.txt' a ... ['/', 'users', 'john', 'foo.txt'] b ... ['users', 'john', 'foo.txt'] False  Test 14: 'foo/bar/baz/loop' drive, path '' 'foo/bar/baz/loop' a ... ['foo', 'bar', 'baz', 'loop'] b ... ['foo', 'bar', 'baz', 'loop'] True  Test 15: 'foo/bar/baz/' drive, path '' 'foo/bar/baz/' a ... ['foo', 'bar', 'baz', ''] b ... [] False  Test 16: '//hostname/foo/bar.txt' drive, path '' '//hostname/foo/bar.txt' a ... ['//', 'hostname', 'foo', 'bar.txt'] b ... ['hostname', 'foo', 'bar.txt'] False