How can you use os.chdir to go to a path minus the last step of it?

For example, a method is passed a path as a parameter, this path might be "C:/a/b/c/d", what if I want to use os.chdir() to change to C:/a/b/c (without the last folder)? Can 开发者_如何转开发os.chdir() take the ".." command?

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os.chdir() can take '..' as argument, yes. However, Python provides a platform-agnostic way: by using os.pardir:

os.chdir(os.pardir)

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You could use os.path.dirname:

In [1]: import os.path

In [2]: os.path.dirname('C:/a/b/c/d')
Out[2]: 'C:/a/b/c'

edit: It's been pointed out that this doesn't remove the last component if the path ends with a slash. As a more robust alternative, I propose the following:

In [5]: os.path.normpath(os.path.join('C:/a/b/c/d', '..'))
Out[5]: 'C:/a/b/c'

In [6]: os.path.normpath(os.path.join('C:/a/b/c/d/', '..'))
Out[6]: 'C:/a/b/c'

The '..' can be replaced with os.path.pardir to make the code even more portable (at least theoretically).

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The os.path module has some functions that are useful for this sort of thing.

os.path.normpath() can be used to convert a path containing references like .. to an absolute path. This would ensure consistent behaviour regardless of how the operating system handles paths.

os.chdir(os.path.normpath("C:/a/b/c/..")) should accomplish what you want.