On Sunday, March 25, 2018 at 10:02:20 AM UTC-5, Jugurtha Hadjar wrote: [...] > Furthermore, the only case I'd use a positional argument is > if I were 100% certain the code will not change, which I'm > not.
And short of you possessing a crystal ball in good working order (mine's currently in the shop!), you must always assume that code will grow over time, and thus, write your code in a manner that is as easy to extend and maintain as possible. > Plus when the API will change (and it will), it will be > harder to deal with it that if it were a keyword argument. Huh? Was that a typo? Did you mean "_not_ a kwarg"??? > If you change the order you'd have to change the whole > codebase where the class/function is instantiated/called, If the args are positional, then yes. > whereas if you use a keyword argument, you could just catch > the old way call, issue a deprecation warning, then route > the call for the new way call. Whew! It _was_ a typo. ':-) > [...] > > Suppose I have a class like this: > > class Foo(object): > def __init__(self, name, height, address): > self.name = name > self.height = height > self.address = address > > Suppose I then want to change it to: > > class Foo(object): > def __init__(self, status, name, address, height): > self.status = status > self.name = name > self.height = height > self.address = address > > > This would totally screw up other parts of the code where > the class is used. I tend to use positional arguments when > it's *way* unlikely the code will ever change, and even > then I probably wouldn't. Positional arguments are not without their practical advantages though. For instance: you don't have to manually unpack the arguments into local vars, plus, you can let Python handle the underflow/overflow of arguments. Of course, the con is that positional arguments do not scale nicely; which leads to nasty backwards incompatible issues. It's a tough call, really. Because as programmers we are inclined to be naturally lazy (it's a virtue!), and thus, we'd prefer to offload as much work as we can on the processor. But if saving a few keystrokes now means hours of painful search&replace sessions later, hmm, probably best to choose the path with the best long-term outcome. -- https://mail.python.org/mailman/listinfo/python-list
