syntax - What does the "at" (@) symbol do in Python?

Example class Pizza(object): def __init__(self): self.toppings = [] def __call__(self, topping): # When using '@instance_of_pizza' before a function definition # the... Read More

python - How do I avoid the "self.x = x; self.y = y; self.z = z" pattern in __init__?

Disclaimer: It seems that several people are concerned about presenting this solution, so I will provide a very clear disclaimer. You should not use this solution. I only provide it as information, s... Read More

python - Class method decorator with self arguments?

Yes. Instead of passing in the instance attribute at class definition time, check it at runtime: def check_authorization(f): def wrapper(*args): print args[0].url return f(*args)... Read More

oop - Real world example about how to use property feature in python?

Other examples would be validation/filtering of the set attributes (forcing them to be in bounds or acceptable) and lazy evaluation of complex or rapidly changing terms. Complex calculation hidden be... Read More

How to bypass python function definition with decorator?

If the goal is to have the same sort of effect in your code that #ifdef WINDOWS / #endif has.. here's a way to do it (I'm on a mac btw). Simple Case, No Chaining >>> def _ifdef_decorator_impl(plat,... Read More

python - How to inject variable into scope with a decorator?

You can't. Scoped names (closures) are determined at compile time, you cannot add more at runtime. The best you can hope to achieve is to add global names, using the function's own global namespace:... Read More

python - Difference between staticmethod and classmethod

Maybe a bit of example code will help: Notice the difference in the call signatures of foo, class_foo and static_foo: class A(object): def foo(self, x): print "executing foo(%s, %s)" % (s... Read More

How do I pass extra arguments to a Python decorator?

Since you are calling the decorator like a function, it needs to return another function which is the actual decorator: def my_decorator(param): def actual_decorator(func): print("Decorat... Read More

python - Decorator execution order

Decorators wrap the function they are decorating. So make_bold decorated the result of the make_italic decorator, which decorated the hello function. The @decorator syntax is really just syntactic su... Read More

python - How to make a chain of function decorators?

If you are not into long explanations, see Paolo Bergantino’s answer. Decorator Basics Python’s functions are objects To understand decorators, you must first understand that functions are objects in... Read More