Nested attr/item getter/setter

[ftobia]

Given a data structure like:

data = {
 'foo': {
     'bar': {
         'baz': 'monkey'
      }
   }
}

I want to do something like operator.itemgetter in a nested fashion.
Something like:

nested_itemgetter('foo', 'bar', 'baz')(data)  == 'monkey'

Note that this is a different behavior than operator.itemgetter. Attention should be paid to writing an API that makes sense given the operator.itemgetter API.

And then, do something equivalent for related functions:

• operator.itemgetter
• operator.getitem
• getattr
• setattr
• operator.attrgetter

Some of those might not make sense, e.g. looks like operator.attrgetter already works nestedly: https://docs.python.org/2/library/operator.html#operator.attrgetter

[RobRuana]

Very cool idea!

Side note: I wasn't notified about this issue... totally weird.

[ftobia]

For my future self:

class nested_itemgetter(object):
    """
    Extends operator.itemgetter to operate on nested data structures.
    >>> data_structure = {
        'foo': {
            'bar': 'baz'
        }
    }
    >>> getter = nested_itemgetter('foo', 'bar')
    >>> getter(data_structure)
    'baz'
    """
    def __init__(self, *args):
        self._args = args

    def __call__(self, obj):
        reduce_target = [obj] + list(self._args)
        return reduce(operator.getitem, reduce_target)