python - 如何从另一个类继承变量

Question

我有一个代码:

class read:
    a = 0
    c = write.c
    def get_num():
        a = 6
        return a


class write:
    c = 0 
    a = read.get_num()
    def do_num(self):
        b = read.get_num()
        self.c = 10
        return b

print(write.c)

问题:

1. 如何获取 print(write.c) 的解决方案最后10对于 c 。
2. 如何创建变量 c排队3等于 c = 0上课write
3. 如何创建变量 c排队3等于 c = 10上课write

Answer 1

1. do_num() 需要设置 write.c 而不是 self.c，以便它设置类属性而不是实例属性。并且您需要调用no_num()。

class write:
    c = 0 
    a = read.get_num()
    def do_num(self):
        b = read.get_num()
        write.c = 10
        return b

w = write()
w.do_num()
print(write.c)

您需要按其他顺序定义类。在定义类之前，您无法访问 write.c。

class write:
    c = 0 
    a = read.get_num()
    def do_num(self):
        b = read.get_num()
        write.c = 10
        return b

class read:
    a = 0
    c = write.c
    def get_num():
        a = 6
        return a

您需要将 read.c 设为一个类属性，以便在使用时读取 write.c 的值。请参阅How to make a class property?了解如何定义类属性。