How to Handle TypeError: Unhashable Type ‘Dict’ Exception in Python

The Python TypeError: unhashable type: 'dict' usually occurs when trying to hash a dictionary, which is an unhashable object. For example, using a dictionary as a key in another dictionary will cause this error. This is because dictionaries only accept hashable data types as a key.

Only immutable objects such as strings, integers and tuples are hashable since they have a single unique value that never changes. Hashing such objects always produces the same result, so they can be used as keys for dictionaries.

TypeError: Unhashable Type: 'Dict' Example

Here’s an example of a Python TypeError: unhashable type: 'dict'thrown when a dictionary is used as the key for another dictionary:

my_dict = {1: 'A', {2: 'B', 3: 'C'}: 'D'}
print(my_dict)

Since a dictionary is not hashable, running the above code produces the following error:

File "test.py", line 1, in <module>
    my_dict = {1: 'A', {2: 'B', 3: 'C'}: 'D'}
TypeError: unhashable type: 'dict'

How to Fix TypeError: Unhashable Type: 'Dict'

The Python TypeError: unhashable type: 'dict' can be fixed by casting a dictionary to a hashable object such as tuple before using it as a key in another dictionary:

my_dict = {1: 'A', tuple({2: 'B', 3: 'C'}): 'D'}
print(my_dict)

In the example above, the tuple() function is used to convert the dictionary to a tuple. The above code runs successfully and produces the correct output:

{1: 'A', (2, 3): 'D'}

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