在 __setattr__()
中有什么方法可以区分来自类或子/继承类内部的属性集,以及来自当前类或子类外部的属性集?
我想从“外部”更改设置属性的工作方式,在我制作模块的情况下,我希望用户在设置属性时与在类内部设置属性时具有不同的逻辑。
例如:
i.x = 5
当从类中调用时通常应该分配 5 并且 i
是它的一个实例,但是当从另一个类中调用时它应该减去 5 而不是设置为 5。
最佳答案
有点低级,但你可以使用 inspect
模块:
import inspect
class A:
def __init__(self):
self.__x = 0
@property
def x(self):
return self.__x
@x.setter
def x(self, value):
f = inspect.currentframe()
if 'self' in f.f_back.f_locals and issubclass(type(f.f_back.f_locals['self']), A):
print('Called from class!')
self.__x = -value
else:
print('Called from outside!')
self.__x = value
def fn(self):
print('Calling A.x from inside:')
self.x = 10
class B(A):
def __init__(self):
super().__init__()
def fn2(self):
print('Calling B.x from inside:')
self.x = 15
a = A()
print("A.x after init:", a.x)
print('Calling A.x from outside')
a.x = 10
print("A.x called from the outside:", a.x)
a.fn()
print("A.x called from the inside:", a.x)
b = B()
print("B.x after init:", b.x)
print('Calling B.x from outside')
b.x = 20
print("B.x called from the outside:", b.x)
b.fn2()
print("B.x called from the inside:", b.x)
打印:
A.x after init: 0
Calling A.x from outside
Called from outside!
A.x called from the outside: 10
Calling A.x from inside:
Called from class!
A.x called from the inside: -10
B.x after init: 0
Calling B.x from outside
Called from outside!
B.x called from the outside: 20
Calling B.x from inside:
Called from class!
B.x called from the inside: -15
关于python - 如何区分类内和类外使用 __setattr__ 设置的属性?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/56550263/