Objects in Python can have attributes — data attributes and functions to work with those (methods). Actually, every object has built-in attributes (try dir(None), dir(True), dir(…), dir(dir) in Python console). For example you have an object person, that has several attributes: name, gender, etc. You access these attributes (be it methods or data objects) usually … Read more
Alex’s answer was good, but providing you with a sample code since you asked for it 🙂 class foo: def __init__(self): self.a = “a” def __getattr__(self, attribute): return “You asked for %s, but I’m giving you default” % attribute >>> bar = foo() >>> bar.a ‘a’ >>> bar.b “You asked for b, but I’m giving … Read more
Yes, but you don’t pass them to getattr(); you call the function as normal once you have a reference to it. getattr(obj, ‘func’)(‘foo’, ‘bar’, 42)
You can do this: getattr(CallMe, variable)() getattr is a builtin method, it returns the value of the named attributed of object. The value in this case is a method object that you can call with ()
__getattr__() and __str__() for an object are found on its class, so if you want to customize those things for a class, you need the class-of-a-class. A metaclass. class FooType(type): def _foo_func(cls): return ‘foo!’ def _bar_func(cls): return ‘bar!’ def __getattr__(cls, key): if key == ‘Foo’: return cls._foo_func() elif key == ‘Bar’: return cls._bar_func() raise AttributeError(key) … Read more
You must call the parent class __setattr__ method: class MyTest(object): def __init__(self, x): self.x = x def __setattr__(self, name, value): if name==”device”: print “device test” else: super(MyTest, self).__setattr__(name, value) # in python3+ you can omit the arguments to super: #super().__setattr__(name, value) Regarding the best-practice, since you plan to use this via xml-rpc I think this … Read more
You get a recursion error because your attempt to access the self.__dict__ attribute inside __getattribute__ invokes your __getattribute__ again. If you use object‘s __getattribute__ instead, it works: class D(object): def __init__(self): self.test=20 self.test2=21 def __getattribute__(self,name): if name==’test’: return 0. else: return object.__getattribute__(self, name) This works because object (in this example) is the base class. By … Read more
There are two basic problems you are running into here: __xxx__ methods are only looked up on the class TypeError: can’t set attributes of built-in/extension type ‘module’ (1) means any solution would have to also keep track of which module was being examined, otherwise every module would then have the instance-substitution behavior; and (2) means … Read more
import sys thismodule = sys.modules[__name__] setattr(thismodule, name, value) or, without using setattr (which breaks the letter of the question but satisfies the same practical purposes;-): globals()[name] = value Note: at module scope, the latter is equivalent to: vars()[name] = value which is a bit more concise, but doesn’t work from within a function (vars() gives … Read more
Overriding __getattr__ should be fine — __getattr__ is only called as a last resort i.e. if there are no attributes in the instance that match the name. For instance, if you access foo.bar, then __getattr__ will only be called if foo has no attribute called bar. If the attribute is one you don’t want to … Read more