TypeError: unhashable type: 'dict' TypeError: unhashable type: 'dict' python python

TypeError: unhashable type: 'dict'


You're trying to use a dict as a key to another dict or in a set. That does not work because the keys have to be hashable. As a general rule, only immutable objects (strings, integers, floats, frozensets, tuples of immutables) are hashable (though exceptions are possible). So this does not work:

>>> dict_key = {"a": "b"}>>> some_dict[dict_key] = TrueTraceback (most recent call last):  File "<stdin>", line 1, in <module>TypeError: unhashable type: 'dict'

To use a dict as a key you need to turn it into something that may be hashed first. If the dict you wish to use as key consists of only immutable values, you can create a hashable representation of it like this:

>>> key = frozenset(dict_key.items())

Now you may use key as a key in a dict or set:

>>> some_dict[key] = True>>> some_dict{frozenset([('a', 'b')]): True}

Of course you need to repeat the exercise whenever you want to look up something using a dict:

>>> some_dict[dict_key]                     # Doesn't workTraceback (most recent call last):  File "<stdin>", line 1, in <module>TypeError: unhashable type: 'dict'>>> some_dict[frozenset(dict_key.items())]  # WorksTrue

If the dict you wish to use as key has values that are themselves dicts and/or lists, you need to recursively "freeze" the prospective key. Here's a starting point:

def freeze(d):    if isinstance(d, dict):        return frozenset((key, freeze(value)) for key, value in d.items())    elif isinstance(d, list):        return tuple(freeze(value) for value in d)    return d


A possible solution might be to use the JSON dumps() method, so you can convert the dictionary to a string ---

import jsona={"a":10, "b":20}b={"b":20, "a":10}c = [json.dumps(a), json.dumps(b)]set(c)json.dumps(a) in c

Output -

set(['{"a": 10, "b": 20}'])True


matomo