问题
My first question, please be gentle. I searched but could not find an answer here or elsewhere.
Note that this question does not apply to unpacking of arguments like *args.
In the python 3.3 documentation for os.removexattr the following is stated:
os.removexattr(path, attribute, *, follow_symlinks=True)
Removes the extended filesystem attribute attribute from path.
attribute should be bytes or str. If it is a string, it is encoded
with the filesystem encoding.
This function can support specifying a file descriptor and not
following symlinks.
Note that the third argument is a star: *
I assumed that this means "specify one attribute or several attributes separated by comma", but when trying to do that, I get an exception:
import os
os.removexattr('M7-AAE-01.jpg', 'user.camera_brand', 'user.camera_model')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: Function takes at most 2 positional arguments (3 given)
I also tried to supply a list of arguments, but that did not work either.
What exactly does the star argument mean in this case? Thank you.
回答1:
The single asterisk *
just means that it is forcing you to use named arguments. In this case if you want to pass a value for follow_symlinks
, you have to pass the argument name.
The idea is you don't having to read function calls like foo(True, False, False)
and not know what those values are doing.
来源:https://stackoverflow.com/questions/20810522/python-documentation-for-os-removexattr-what-does-the-star-argument-mea