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+--- Thread: python 3.8 and positional arguments (/thread-19018.html)
python 3.8 and positional arguments - vojo - Jun-10-2019
saw the plans for 3.8. Trying to understand how these 2 functions would be handled
def pos_key (pos only * pos or key / key only):
blah blah
def whatever( my_cool_var = 4 * 5 / 2):
blah blah
second not allowed (maybe never has been)?
RE: python 3.8 and positional arguments - Larz60+ - Jun-10-2019
Python-forum.io is not the the official site of python
Please post your question here: https://www.python.org/community/lists/
Thank you.
RE: python 3.8 and positional arguments - DeaD_EyE - Jun-10-2019
Haven't tried it, but I guess the second example does a multilication and then a division. Have never seen this in real world applications. Those constants should not be defined in the function signature.
RE: python 3.8 and positional arguments - metulburr - Jun-10-2019
linking
https://docs.python.org/3.8/whatsnew/3.8.html
I dont think that is what they mean when they are adding / (the second example)
https://www.python.org/dev/peps/pep-0570/
RE: python 3.8 and positional arguments - DeaD_EyE - Jun-10-2019
Explained with code using your whatever function:
In [6]: def whatever(my_cool_var=4 * 5 / 2):
...: print(my_cool_var)
...:
In [7]: whatever()
10.0
In [8]: whatever(2)
2
In [9]: whatever(my_cool_var=2)
2
In [10]: def whatever(my_cool_var=4 * 5 / 2, /):
...: print(my_cool_var)
...:
In [11]: whatever(my_cool_var=2)
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-11-65f31df15028> in <module>
----> 1 whatever(my_cool_var=2)
TypeError: whatever() got some positional-only arguments passed as keyword arguments: 'my_cool_var'
In [12]: whatever(2)
2
In [13]: whatever()
10.0This is interesting for library developers who want to enforce the use of positional arguments, followed by keyword-arguments.Just read the PEP.