问题
Currently I do not understand, why pythons os.path.dirname behave like it does.
Let's assume I have the following script:
# Not part of the script, just for the current sample
__file__ = 'C:\\Python\\Test\\test.py'
Then I try to get the absolute path to the following directory: C:\\Python\\doc\\py
With this code:
base_path = os.path.dirname(os.path.dirname(os.path.realpath(__file__)) + '\\..\\doc\\py\\')
But why does the method os.path.dirname does not resolve the path, and print out (print (base_path):
C:\Python\Test\..\doc\py
I've expected the method to resolve the path to:
C:\Python\Test\doc\py
I just know this behaviour from the .NET Framework, that getting directory paths will always resolve the complete path and remove directory changes with ..\\. What do I have in Python for possibilities to do this?
回答1:
Look into os.path.normpath
Normalize a pathname by collapsing redundant separators and up-level references so that A//B, A/B/, A/./B and A/foo/../B all become A/B. This string manipulation may change the meaning of a path that contains symbolic links. On Windows, it converts forward slashes to backward slashes.
The reason os.path.dirname works the way it does is because it's not very smart - it even work for URLs!
os.path.dirname("http://www.google.com/test") # outputs http://www.google.com
It simply chops off anything after the last slash. It doesn't look at anything before the last slash, so it doesn't care if you have /../ in there somewhere.
回答2:
os.path.normpath() will return a normalized path, with all references to the current or parent directory removed or replaced appropriately.
来源：https://stackoverflow.com/questions/34489459/python-os-path-dirname-returns-unexpected-path-when-changing-directory