decorator – Page 13 – Tarik Billa

Creating a singleton in Python

August 28, 2022 by Tarik

Use a Metaclass I would recommend Method #2, but you’re better off using a metaclass than a base class. Here is a sample implementation: class Singleton(type): _instances = {} def __call__(cls, *args, **kwargs): if cls not in cls._instances: cls._instances[cls] = super(Singleton, cls).__call__(*args, **kwargs) return cls._instances[cls] class Logger(object): __metaclass__ = Singleton Or in Python3 class Logger(metaclass=Singleton): … Read more

How do I make function decorators and chain them together?

August 23, 2022 by Tarik

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 Python. This has important consequences. Let’s see why with a simple example : def shout(word=”yes”): return word.capitalize()+”!” print(shout()) # outputs : ‘Yes!’ # As an object, … Read more