Python how to create a dict of dict of list with defaultdict

Question

How do I create a dict of dict of lists using defaultdict? I am getting the following error.

>>> from collections import defaultdict
>>> a=         


        

Answer 1

You may have to do like this.

>>> from collections import defaultdict
>>> a=defaultdict()
>>> a["testkey"]=None
>>> a["testkey"]=defaultdict(list)
>>> a["testkey"]["list"]=["a","b","c"]
>>> a
defaultdict(None, {'testkey': defaultdict(, {'list': ['a', 'b', 'c']})})