Comparing two paths in python

Question

Consider:

path1 = "c:/fold1/fold2"
list_of_paths = ["c:\\fold1\\fold2","c:\\temp\\temp123"]

if path1 in list_of_paths:
    print "found"

I would like the if statement to return True, but it evaluates to False, since it is a string comparison.

How to compare two paths irrespective of the forward or backward slashes they have? I'd prefer not to use the replace function to convert both strings to a common format.

Solution 1

Use os.path.normpath to convert c:/fold1/fold2 to c:\fold1\fold2:

>>> path1 = "c:/fold1/fold2"
>>> list_of_paths = ["c:\\fold1\\fold2","c:\\temp\\temp123"]
>>> os.path.normpath(path1)
'c:\\fold1\\fold2'
>>> os.path.normpath(path1) in list_of_paths
True
>>> os.path.normpath(path1) in (os.path.normpath(p) for p in list_of_paths)
True

• os.path.normpath(path1) in map(os.path.normpath, list_of_paths) also works, but it will build a list with entire path items even though there's match in the middle. (In Python 2.x)

On Windows, you must use os.path.normcase to compare paths because on Windows, paths are not case-sensitive.

Solution 2

All of these answers mention os.path.normpath, but none of them mention os.path.realpath:

os.path.realpath(path)

Return the canonical path of the specified filename, eliminating any symbolic links encountered in the path (if they are supported by the operating system).

New in version 2.2.

So then:

if os.path.realpath(path1) in (os.path.realpath(p) for p in list_of_paths):
    # ...

Solution 3

The os.path module contains several functions to normalize file paths so that equivalent paths normalize to the same string. You may want normpath, normcase, abspath, samefile, or some other tool.

Solution 4

If you are using python-3, you can use pathlib to achieve your goal:

import pathlib
path1 = pathlib.Path("c:/fold1/fold2")
list_of_paths = [pathlib.Path(path) for path in ["c:\\fold1\\fold2","c:\\temp\\temp123"]]
assert path1 in list_of_paths

Solution 5

Store the list_of_paths as a list instead of a string:

list_of_paths = [["c:","fold1","fold2"],["c","temp","temp123"]]

Then split given path by '/' or '\' (whichever is present) and then use the in keyword.

View more solutions

Comments

[Jagannath Ks]

Hi Ashwin, I am not sure which variable has what slash as both are generated dynamically and i cannot replace every string as i would be surfing large data

[ondra]

And add os.path.normcase to convert to lowercase on windows - as windows should be case insensitive for comparisons.

[Aswin Murugesh]

But the OP says there may be any of the slashes in any place

[falsetru]

@AswinMurugesh, Thank you for comment. I added a version that will handle such case.

[Jagannath Ks]

list1 = ['a\\b\\c','x\y\z'], list2 = ['a\\b','x\y'], lis3 = [os.path.normpath(item) for item in list1 if os.path.isdir(item)], list4 = [os.path.normpath(item) for item in list2 if os.path.isdir(item)] for directory in list4: for root, dirnames, filenames in os.walk(directory): if os.path.normpath(root) in list3: print "found" but this code somehow fails !

[falsetru]

@JagannathKs, It works for me (printing found) after slight modification (lis3 -> list3, x\y -> x\\y, x\y\z -> x\\y\\z) and creation of the directorys a\b\c, x\y\z

[cbare]

There's still a gotcha on windows: 'c:\\users\\administrator\\foo.txt' is the same file as 'c:\\users\\admini~1\\foo.txt' thanks to the lameness that is 8.3 filenames.

[Seng Cheong]

I think you want to use os.path.realpath, to cover cases like @cbare mentions.

[baky]

os.path.normpath is for normalizing the paths, we should use os.path.realpath for canonicalizing.

[user4815162342]

@baky That depends on the exact requirements. Since the OP requested comparison "irrespective of forward or backward slash", which normpath fulfills. It is of course possible that the OP misstated their requirements two and a half years ago, but that would be guessing.

[mattst]

+1 for os.path.samefile(path1, path2). Using this removes the need to use normpath(), realpath(), or normcase() (on Windows OSes), before performing a string comparrison. However it requires both paths to exist on the filesystem or a FileNotFoundError exception will be raised and it does not resolve home relative paths, e.g. ~/Path/To/File, for these use expanduser(). Note: Python 3.2 added samefile() support for Windows OSes.

[Stefan]

+1 also for samefile and just to mention: despite the name "samefile" also allows for checking directories! see docs.python.org/3/library/os.path.html

[Guimoute]

To add on @falsetru's answer, the nice thing about this solution is that it understands when you move to the parent folder, so os.path.normpath("A\\B\\C\\..\\..\\test.txt") == "A\\test.txt".