Special method call

#python #datastructure #code

• Objects in python can be callable as well using the special method __call__

class BingoCage:

    def __init__(self, items):
        self._items = list(items)
        random.shuffle(self._items)

    def pick(self):
        try:
            return self._items.pop()
        except IndexError:
            raise LookupError('pick from empty BingoCage')

    def __call__(self):
        return self.pick()

>>> bingo = BingoCage(range(3))
>>> bingo.pick()
1
>>> bingo()
0
>>> callable(bingo)
True

• Objects similar to the functions
• Implementation of decorators using __call__. Decorators need to invoked

Sources

• Fluent Python - Luciano Ramalho - 2023 - Second Edition - Web Edition