Python accessing similarly named class and instance attributes

Question

I have a class with class and instance attributes with the same name. Is there a way to return their respected value based on the context they are accessed?

Example:

class A:
    b = 'test'
    @property
    def b(self):
        return 'not test'

Desired Results:

>>> A().b
'not test'
>>> A.b
'test'

Actual Results:

>>> A().b
'not test'
>>> A.b
<property object at 0x03ADC640>

you named your `property` that, which replaced your previous assignment to `b`. You *could* use an actual instance attribute — juanpa.arrivillaga, Jul 10 '20 at 20:09
Is there a reason not to use different names for different attributes? — zvone, Jul 10 '20 at 20:48
My current implementation uses different names (`b` for the instance variable and `b_` for the class variable). — Dillon Miller, Jul 10 '20 at 21:06

zvone · Answer 1 · 2020-07-10T20:57:17.217

I have no idea why you want that, but this would work:

class ClassWithB(type):
    @property
    def b(self):
        return 'test'


class A(metaclass=ClassWithB):
    @property
    def b(self):
        return 'not test'

It behaves like this:

>>> A.b
'test'
>>> A().b
'not test'

You could also use e.g. a descriptor:

class B:
    def __get__(self, obj, type_=None):
        if obj is None:
            return 'test'
        else:
            return 'not test'

class A:
    b = B()

score 0 · Answer 2 · answered Jul 10 '20 at 20:12

0

No - the method shadows the instance - see this for more information https://stackoverflow.com/a/12949375/13085236

answered Jul 10 '20 at 20:12

Rusty Widebottom

985
2
5
14

Python accessing similarly named class and instance attributes

2 Answers2