---
title: Python Frozenset
---
**`frozenset` basic info**
The `frozenset` type is a builtin set types which is immutable and hashable -- its contents cannot be altered after it is created; however, it can be used as a dictionary key or as an element of another set. Frozensets are like sets except that they cannot be changed, i.e they are immutale.
>>> cities = frozenset(["Frankfurt", "Basel", "Freiburg"])
>>> cities.add("Strasbourg")
Traceback (most recent call last):
File "", line 1, in
AttributeError: 'frozenset' object has no attribute 'add'
>>>
`frozenset` constructor:
`frozenset([iterable])`
The iterable contains elements to initialize the frozenset with. The iterable can be set, dictionary, tuple etc. If no parameter is passed, the `frozenset()` method returns an empty frozenset.
**Examples**
>>> vowels = ('a', 'e', 'i', 'o', 'u')
>>> fSet = frozenset(vowels)
>>> print("The frozen set is: ", fSet)
The frozen set is: frozenset({'i', 'e', 'a', 'u', 'o'})
>>> print("The empty frozen set is: ", frozenset())
The empty frozen set is: frozenset()
>>>
**Another Example**
>>> person = {"name": "John", "age": 23, "sex": "male"}
>>> fSet = frozenset(person)
>>> print("The frozen set is: ", fSet)
The frozen set is: frozenset({'sex', 'name', 'age'})
>>>
**Additional Information**
Python Frozenset()
Set Types -- set, frozenset
Python Tutorial: Sets and Frozen sets