问题：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绝对路径以“ /”开头，而Windows则以字母“ C：”或“ \”开头。python是否具有标准功能来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?
回答 0
os.path.isabsTrue如果路径是绝对的，False则返回，否则返回。该文档说它可以在Windows中运行（我可以确认它可以在Linux中正常运行）。
os.path.isabs(my_path)
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)
回答 1
如果您真正想要的是绝对路径，则不必费心检查它是否是绝对路径，只需获取abspath：
import os
print os.path.abspath('.')
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('.')
回答 2
回答 3
import os.path
os.path.isabs('/home/user')
True
os.path.isabs('user')
False
import os.path
os.path.isabs('/home/user')
True
os.path.isabs('user')
False
回答 4
实际上，我认为以上答案均未解决真正的问题：跨平台路径。os.path的作用是加载OS依赖的’path’库版本。因此解决方案是显式加载相关的（OS）路径库：
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
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
回答 5
从python 3.4 pathlib可用。
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:/')
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:/')
回答 6
换句话说，如果您不在当前工作目录中，那有点脏，但是对我有用。
import re
path = 'my/relative/path'
# path = '..my/relative/path'
# path = './my/relative/path'
pattern = r'([a-zA-Z0-9]|[.])+/'
is_ralative = bool(pattern)
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)
