1>>> s = pd.Series([1, 2, 3, 4])
2>>> s.to_dict()
3{0: 1, 1: 2, 2: 3, 3: 4}
4>>> from collections import OrderedDict, defaultdict
5>>> s.to_dict(OrderedDict)
6OrderedDict([(0, 1), (1, 2), (2, 3), (3, 4)])
7>>> dd = defaultdict(list)
8>>> s.to_dict(dd)
9defaultdict(<class 'list'>, {0: 1, 1: 2, 2: 3, 3: 4})
10