TypeError: Unhashable Type 'dict'

Why This Happens

Like lists, dictionaries are mutable and therefore unhashable. They cannot be used as dictionary keys or set elements. If you need to use dict-like data as a key, convert it to a tuple of sorted items or a frozenset.

The Problem

seen = set()
record = {'name': 'Alice', 'age': 30}
seen.add(record)

The Fix

seen = set()
record = {'name': 'Alice', 'age': 30}
seen.add(frozenset(record.items()))

Step-by-Step Fix

1. 1

   Convert to hashable type

   Use frozenset(dict.items()) or tuple(sorted(dict.items())).

2. 2

   Use a different key

   If the dict has a unique identifier field, use that as the key instead.

3. 3

   Consider named tuples

   Use collections.namedtuple or dataclasses with frozen=True for hashable record types.