John Ladasky wrote: > Hi folks, > > I'm trying to make some of Python class definitions behave like the ones I > find in professional packages, such as Matplotlib. A Matplotlib class can > often have a very large number of arguments -- some of which may be > optional, some of which will assume default values if the user does not > override them, etc.
Personally, I'd rather not copy that kind of interface. > I have working code which does this kind of thing. I define required > arguments and their default values as a class attribute, in an > OrderedDict, so that I can match up defaults, in order, with *args. I'm > using set.issuperset() to see if an argument passed in **kwargs conflicts > with one which was passed in *args. I use set.isdisjoint() to look for > arguments in **kwargs which are not expected by the class definition, > raising an error if such arguments are found. Why do you rely on a homebrew solution instead of actually calling the function or initializer? > Even though my code works, I'm finding it to be a bit clunky. And now, > I'm writing a new class which has subclasses, and so actually keeps the > "extra" kwargs instead of raising an error... This is causing me to > re-evaluate my original code. > > It also leads me to ask: is there a CLEAN and BROADLY-APPLICABLE way for > handling the *args/**kwargs/default values shuffle that I can study? Or > is this sort of thing too idiosyncratic for there to be a general method? > > Thanks for any pointers! inspect.getcallargs() may be worth a look. -- https://mail.python.org/mailman/listinfo/python-list