7.6. Sequence Unordered

7.6.1. Both

• unordered

• impossible to getitem and slice

• unique elements

• only hashable elements

7.6.2. Frozenset

• immutable

7.6.3. Set

• mutable

7.6.4. Memory Footprint

>>> from sys import getsizeof
>>>
>>>
>>> a = {1, 2, 3}
>>> b = frozenset({1, 2, 3})
>>>
>>> getsizeof(a)
216
>>>
>>> getsizeof(b)
216