如何使用Python以跨平台方式检查路径是绝对路径还是相对路径？

UNIX absolute path starts with ‘/’, whereas Windows starts with alphabet ‘C:’ or ‘\’. Does python has a standard function to check if a path is absolute or relative?

os.path.isabs returns True if the path is absolute, False if not. The documentation says it works in windows (I can confirm it works in Linux personally).

os.path.isabs(my_path)

And if what you really want is the absolute path, don’t bother checking to see if it is, just get the abspath:

import os

print os.path.abspath('.')

Use os.path.isabs.

import os.path

os.path.isabs('/home/user')
True

os.path.isabs('user')
False

Actually I think none of the above answers addressed the real issue: cross-platform paths. What os.path does is load the OS dependent version of ‘path’ library. so the solution is to explicitly load the relevant (OS) path library:

import ntpath
import posixpath

ntpath.isabs("Z:/a/b/c../../H/I/J.txt")
    True
posixpath.isabs("Z:/a/b/c../../H/I/J.txt")
    False

From python 3.4 pathlib is available.

In [1]: from pathlib import Path

In [2]: Path('..').is_absolute()
Out[2]: False

In [3]: Path('C:/').is_absolute()
Out[3]: True

In [4]: Path('..').resolve()
Out[4]: WindowsPath('C:/the/complete/path')

In [5]: Path('C:/').resolve()
Out[5]: WindowsPath('C:/')

another way if you are not in current working directory, kinda dirty but it works for me.

import re
path = 'my/relative/path'
# path = '..my/relative/path'
# path = './my/relative/path'

pattern = r'([a-zA-Z0-9]|[.])+/'
is_ralative = bool(pattern)