在循环中重写类变量

class Example:
    class_variable = 0

    def loop(self):
        for i in range(5):
            self.class_variable = i

example1 = Example()
example2 = Example()

example1.loop()
print(example1.class_variable)  # 输出：4
print(example2.class_variable)  # 输出：4

class Example:
    def loop(self):
        instance_variable = 0

        for i in range(5):
            instance_variable = i

        return instance_variable

example1 = Example()
example2 = Example()

print(example1.loop())  # 输出：4
print(example2.loop())  # 输出：4