how to create a python object where every attribute is None

Question

I'm not sure if this can be done, but I would like an object where you can query any attribute, and it just returns None, instead of an error.

eg.

>>> print(MyObject.whatever)
None
>>> print(MyObject.abc)
None
>>> print(MyObject.thisisarandomphrase)
None

without manually assigning all of these values in the object's __init__ function

Out of curiosity, could you tell us why you want to do this? — Stuart
– Stuart, Commented Mar 16, 2022 at 16:19
I'm making a spreadsheet and I want the cells to be empty if the attribute doesnt exist in that particular object — aloea
– aloea, Commented Mar 16, 2022 at 16:23
Then I would assume you still want it to return the attribute if the attribute does exist? — Stuart
– Stuart, Commented Mar 16, 2022 at 16:30
the answer is no for complicated reasons but your answer will be useful to someone else so thanks anyway :) — aloea
– aloea, Commented Mar 16, 2022 at 16:35

mozway · Accepted Answer · 2022-03-16 16:16:25Z

3

You can define __getattribute__:

class MyObject:
    def __getattribute__(self, name):
        return None  # or simply return
    
x = MyObject()
print(x.abc)
print(x.xyz)

output:

None
None

NB. note that is might not work with all attributes, there are reserved words, e.g. x.class

answered Mar 16, 2022 at 16:16

mozway

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Comments

Senpai · Accepted Answer · 2022-03-16 16:16:50Z

0

No sure if I understood your question (not very good at english), but i think you could try using hasattr (https://docs.python.org/3/library/functions.html#hasattr) to check if the attribute exist and return wathever you want if it doesnt

answered Mar 16, 2022 at 16:16

Senpai

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Comments

Stuart · Accepted Answer · 2022-03-16 16:32:18Z

0

In case you still want the class to return actual attributes when they do exist, you could have __getattribute__ catch attribute errors:

class MyObject(object):
    def __getattribute__(self, name):
        try:
            return object.__getattribute__(self, name)
        except AttributeError:
            return None

answered Mar 16, 2022 at 16:32

Stuart

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Comments

jackal · Accepted Answer · 2022-03-16 16:41:31Z

0

I would imagine that if the attribute does actually exist that you'd want its value, therefore I propose:

class MyClass:
    def __init__(self):
        self.a = 1
    def __getattr__(self, name):
        try:
            return super(MyClass, self).__getattr__(name)
        except AttributeError:
            pass
        return None

mc = MyClass()

print(mc.a)
print(mc.b)

Output:

1
None

answered Mar 16, 2022 at 16:41

jackal

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