Python 类变量

Python 类变量

除了定义对象属性外，Python 也可以定义类变量

示例

class ClassVariable:
    __object_count = 0

    def __init__(self, name: str):
        self.name = name
        ClassVariable.__object_count = ClassVariable.__object_count + 1

    def __del__(self):
        ClassVariable.__object_count = ClassVariable.__object_count - 1

    @staticmethod
    def get_object_count() -> int:
        return ClassVariable.__object_count


def test_class_variable():
    v1 = ClassVariable("v1")
    v2 = ClassVariable("v2")
    assert ClassVariable.get_object_count() == 2
    v3 = ClassVariable("v3")
    assert ClassVariable.get_object_count() == 3
    del v2
    assert ClassVariable.get_object_count() == 2