DotNestedDict

datastructures.py

class DotNestedDict(dict):
    """
    Working with nested dicts (common with mongodb resources) in
    a easy way

    nested = DotNestedDict({
        'lvl1': {'lvl2': {'lvl3': 'here'}},
        'collection': [0, 1, 2, 3, {'nested': 4}],
    })

    assert nested['lvl1.lvl2.lvl3'] == 'here'
    assert nested.get('lvl1.lvl2.lvl3') == 'here'

    assert nested['collection.4.nested'] == 4

    # Errors
    assertRaises nested['lvl1.lvl2.fake'] == KeyError('fake')
    assert nested.get('lvl1.lvl2.fake', 3) == 3

    TODO: doc as doctest
    """

    def _intize(self, key):
        try:
            return int(key)
        except ValueError:
            return key

    def __getitem__(self, key):
        orig_get = super(DotNestedDict, self).__getitem__
        try:
            return orig_get(key)
        except KeyError:
            if not isinstance(key, basestring):
                raise
            bits = filter(bool, key.split('.'))
            current = orig_get(bits[0])
            for bit in bits[1:]:
                try:
                    bit = self._intize(bit)
                    current = current.__getitem__(bit)
                except AttributeError:
                    raise KeyError('%s' % bit)

            return current

    def __getattr__(self, key):
        try:
            return self.__getitem__(key)
        except KeyError as e:
            raise AttributeError(e)

    def get(self, key, default=None):
        try:
            return self[key]
        except:
            return default