On Thu, Mar 22, 2012 at 3:51 AM, Steven Lehar <sle...@gmail.com> wrote: > It seems to me that the Python class system is needlessly confusing. Am I > missing something?
Explicit `self` is slightly annoying, but you'll get over it quickly (trust me). > For example in the class Complex given in the documentation > > class Complex: > def __init__(self, realpart, imagpart): > self.r = realpart > self.i = imagpart > > x = Complex(3.0, -4.5) > > I initially found it profoundly confusing that __init__( ) calls for 3 > arguments, but you call Complex( ) with 2. That's not at all unique to __init__(). > Furthermore, why not call the > initialization function after the class name as is done in other languages? Yech. That would add another step to renaming a class and make referring to the superclass initializer method rather difficult. It would also break the "all special methods have underscored names" rule. Perhaps you'll find the following instructive: Python 2.7.1 (r271:86832, Jul 31 2011, 19:30:53) >>> class Foo(object): ... def __init__(self): ... pass ... >>> Foo() <__main__.Foo object at 0x100fd5750> >>> Bar = Foo >>> Bar.__name__ = "Bar" >>> del Foo >>> # look Ma, I've renamed the class! >>> Bar() <__main__.Bar object at 0x100fd57d0> How would your scheme account for this possibility? > Isn't that the simplest conceptually? Demonstrating with the above example: > > class Complex: > def Complex(realpart, imagpart): > Complex.r = realpart > Complex.i = imagpart Your change of "self" to "Complex" in the method body here makes no sense to me. > x = Complex(3.0, -4.5) > > Is there a good reason why classes cannot be defined that way? (Besides the > problem of backward-compatibility) Mostly historical, IMO. But here are some justifications for explicit `self`: http://docs.python.org/faq/design.html#why-must-self-be-used-explicitly-in-method-definitions-and-calls http://neopythonic.blogspot.com/2008/10/why-explicit-self-has-to-stay.html Cheers, Chris R. -- http://blog.rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
