python中os.path.isabs(path)的分析

sexevil

　　这个本身是小组朋友问的问题，感觉不错，我给出的回答
　　问：
　　>>> os.path.isabs("/home")
True
>>> os.path.isabs("/home/..")
True
>>> os.path.isabs("home/..")
False
这里第二个应该是相对路径吧？ 应该返回False？
　　答：
　　首先，给段资料
The current os.path.isabs documentation says:
> isabs(path)
>    Return True if path is an absolute pathname (begins with a slash).
The "begins with a slash" part is incorrect since certain systems use a
different pathname notation.
For example, on Macintosh (where os.sep == ":") this is an absolute
pathname:
hardDriveName:folderName1:folderName2:fileName.ext
...and this is a relative one:
:folderName1:fileName.ext
Moreover, on Windows os.path.isabs('\\') returns True since '\\' is an
alias for the current drive letter (e.g. C:\\) hence, independently from
what said before, the documentation should include also the "backslash"
term.
It turns out that on Windows there are really 4 different kinds of paths:
1) Completely relative, e.g. foo\bar
2) Completely absolute, e.g. c:\foo\bar or \\server\share
3) Halfbreeds with no drive, e.g. \foo\bar
4) Halfbreeds relative to the current working directory on a specific drive, e.g. c:foo\bar
Python 2.5's os.path.isabs() method considers both (2) and (3) to be absolute;
然后，分析
|这里第二个应该是相对路径吧？ 应该返回False？
根据， linux中absolute *is*
begins with a slash, so return True
说说，第三个吧，你除非在"/"目录下，要不然在其他目录下当然是错的，应为这个路径就不对
而，我在"/"目录下也试了，也返回False，那是因为没有以slash开始
linux中，你只用记下上面那句话就好，其他系统看上面的资料