Python frozenset()

The frozenset() function returns frozenset object that cannot be modified. It contains an unordered collection of objects and it is unchangeable, so it can be used as a key in Dictionary.

frozenset([iterable]) #Where iterable can be a list, string, tuple, dictionary , set etc
 

frozenset() Parameters:

The frozenset() function takes a single parameter. If the iterable argument is given, it returns a frozenset from it. The iterable contains elements to initialize the frozenset.

frozenset() Return Value

Return value is a immutable (cannot modify) frozen set of a given iterable.

Examples of frozenset() method in Python

# tuple of vowels
vowels = ('a', 'e', 'i', 'o', 'u')

fSet = frozenset(vowels)
print('The frozen set is:', fSet)
print('The empty frozen set is:', frozenset())

# frozensets are immutable
fSet.add('v')
 

Output:

The frozen set is: frozenset({'a', 'o', 'u', 'i', 'e'})
The empty frozen set is: frozenset()
Traceback (most recent call last):
  File ", line 8, in 
    fSet.add('v')
AttributeError: 'frozenset' object has no attribute 'add'

fs = frozenset([1, 2, 3, 4, 5, 4, 3])
for x in fs:
    print(x)
 

Output:

1
2
3
4
5

# random dictionary pers "John", "age": 23, "sex": "male"}

fSet = frozenset(person)
print('The frozen set is:', fSet)
 

Output:

The frozen set is: frozenset({'name', 'sex', 'age'})

# Frozensets
# initialize A and B
A = frozenset([1, 2, 3, 4])
B = frozenset([3, 4, 5, 6])

# copying a frozenset
C = A.copy()  # Output: frozenset({1, 2, 3, 4})
print(C)

# union
print(A.union(B))  # Output: frozenset({1, 2, 3, 4, 5, 6})

# intersection
print(A.intersection(B))  # Output: frozenset({3, 4})

# difference
print(A.difference(B))  # Output: frozenset({1, 2})

# symmetric_difference
print(A.symmetric_difference(B))  # Output: frozenset({1, 2, 5, 6})
 

Output:

frozenset({1, 2, 3, 4})
frozenset({1, 2, 3, 4, 5, 6})
frozenset({3, 4})
frozenset({1, 2})
frozenset({1, 2, 5, 6})

# Frozensets
# initialize A, B and C
A = frozenset([1, 2, 3, 4])
B = frozenset([3, 4, 5, 6])
C = frozenset([5, 6])

# isdisjoint() method
print(A.isdisjoint(C))  # Output: True

# issubset() method
print(C.issubset(B))  # Output: True

# issuperset() method
print(B.issuperset(C))  # Output: True
 

Output:

True
True
True