How to change behavior of dict() for an instance

Question

So I\'m writing a class that extends a dictionary which right now uses a method \"dictify\" to transform itself into a dict. What I would like to do instead though is change it

Answer 1

You need to override __iter__.

def __iter__(self): 
    return iter((k, (v.dictify() if isinstance(v, dict) else v)) 
                for (k, v) in self.items())

Instead of self.items(), you should use self.iteritems() on Python 2.

Edit: OK, This seems to be your problem:

>>> class B(dict): __iter__ = lambda self: iter(((1, 2), (3, 4)))
... 
>>> b = B()
>>> dict(b)
{}
>>> class B(list): __iter__ = lambda self: iter(((1, 2), (3, 4)))
... 
>>> b = B()
>>> dict(b)
{1: 2, 3: 4}

So this method doesn't work if the object you're calling dict() on is a subclass of dict.

Edit 2: To be clear, defaultdict is a subclass of dict. dict(a_defaultdict) is still a no-op.