Question

I understand how both __init__ and __new__ work.
I’m wondering if there is anything __init__ can do that __new__ cannot?

i.e. can use of __init__ be replaced by the following pattern:

class MySubclass(object):
    def __new__(cls, *args, **kwargs):
        self = super(MySubclass, cls).__new__(cls, *args, **kwargs)
        // Do __init__ stuff here
        return self

I’m asking as I’d like to make this aspect of Python OO fit better in my head.

Answer 1

One possible answer from guido’s post (thanks @fraca7):

For example, in the pickle module, __new__ is used to create instances when unserializing objects. In this case, instances are created, but the __init__ method is not invoked.

Any other similar answers?

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I’m accepting this answer as a ‘yes’ to my own question:

I’m wondering if there is anything __init__ can do that __new__ cannot?

Yes, unlike __new__, actions that you put in the __init__ method will not be performed during the unpickling process. __new__ cannot make this distinction.