Custom iteration behavior in dict subclass

Question

I have a class that is a subclass of standard dict:

class Result(dict):

    """ Dict-like object with special methods """

    def content(self):
        return self.__getitem__('_content')

    def attrs(self):
        return self.__getitem__('_attrs')

A sample representation in this object:

{
    '_attrs': {'id': 1},
    'description': 'testtest',
    'calories': 1234,
    '_content': 'Sample content',
    'name': 'qwerty',
    'price': 12390
}

I want my class to skip records with underscored keys while iteration.

# data is Result()
>>> for item in data:
>>>    print(item)

'description'
'calories'
'name'
'price'

How can I achieve that?

UPDATE: Besides of correct answer I have also overrided keys() and items() methods to hide underscore keys even if this methods will be used in iteration:

def __iter__(self):
    for key in self.keys():
        yield key

def keys(self):
    return [key for key in super().keys() if key not in ['_attrs', '_content']]

def items(self):
    return [(key, value) for key, value in super().items() if key not in ['_attrs', '_content']]

Answer 1

Just implement __iter__. It's important to use .keys(), in order to avoid infinite recursion:

class Result(dict):
    def __iter__(self):
        for key in self.keys():
            if not(isinstance(key, str) and key.startswith("_")):
                yield key

Then it will be skipped in iteration:

>>> r=Result({1:1,"_foo":2, "bar":3})
>>> for item in r:
...     print(item)
...
1
bar