python-2.x

I want to override my Python class's __getattribute__ and __setattr__ methods. My use case is the usual one: I have a few special names that I want to handle, and I want the default behavior for anything else. For __getattribute__ , it seems that I can request the default behavior simply by raising AttributeError . However, how can I achieve the same in __setattr__ ? Here is a trivial example, implementing a class with immutable fields "A", "B", and "C". class ABCImmutable(SomeSuperclass): def __getattribute__(self, name): if name in ("A", "B", "C"): return "Immutable value of %s" % name else:

When "deconstructing" a tuple, I can use _ to denote tuple elements I'm not interested in, e.g. >>> a,_,_ = (1,2,3) >>> a 1 Using Python 2.x, how can I express the same with function arguments? I tried to use underscores: >>> def f(a,_,_): return a ... File "<stdin>", line 1 SyntaxError: duplicate argument '_' in function definition I also tried to just omit the argument altogether: >>> def f(a,,): return a File "<stdin>", line 1 def f(a,,): return a ^ SyntaxError: invalid syntax Is there another way to achieve the same? Here's what I do with unused arguments: def f(a, *unused): return a A

I'm getting this error TypeError: super() takes at least 1 argument (0 given) using this code on python2.7.11: class Foo(object): def __init__(self): pass class Bar(Foo): def __init__(self): super().__init__() Bar() The workaround to make it work would be: class Foo(object): def __init__(self): pass class Bar(Foo): def __init__(self): super(Bar, self).__init__() Bar() It seems the syntax is specific to python 3. So, what's the best way to provide compatible code between 2.x and 3.x and avoiding this error happening? Yes, the 0-argument syntax is specific to Python 3, see What's New in Python 3

def pi(): prompt=">>> " print "\nWARNING: Pi may take some time to be calculated and may not always be correct beyond 100 digits." print "\nShow Pi to what digit?" n=raw_input(prompt) from decimal import Decimal, localcontext with localcontext() as ctx: ctx.prec = 10000 pi = Decimal(0) for k in range(350): pi += (Decimal(4)/(Decimal(8)*k+1) - Decimal(2)/(Decimal(8)*k+4) - Decimal(1)/(Decimal(8)*k+5) - Decimal(1)/(Decimal(8)*k+6)) / Decimal(16)**k print pi[:int(n)] pi() Traceback (most recent call last): File "/Users/patrickcook/Documents/Pi", line 13, in <module> pi() File "/Users/patrickcook

Possible Duplicate: Why can’t Python handle true/false values as I expect? Seems a stupid question, but why is the following statement in Python not explicitly forbidden? >> True=False >> True False How is True and False handled by Python interpreter? True , just like str or any other builtin, is just a name that exists in the scope by default. You can rebind it like any other such name. Python actually has very few reserved words . All the rest are subject to redefinition. It's up to you to be careful! >>> True = False False In the above assignment, True is just a variable like any other

Disclaimer: I'm looking for a Python 2.6 solution, if there is one. I'm looking for a function that returns a single value when passed a single value, or that returns a sequence when passed multiple values: >>> a = foo(1) 2 >>> b, c = foo(2, 5) >>> b 3 >>> c 6 To be clear, this is in an effort to make some function calls simply look nicer than: a, = foo(1) or a = foo(1)[0] Right now, the inelegant solution is something along these lines: def foo(*args): results = [a + 1 for a in args] return results if len(results) > 1 else results[0] Is there any syntactic sugar (or functions) that would make