Python

Frozen set in Python

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Frozen set in Python

It is another type of set object that is immutable which means when we create this we can’t modify it once it is created.

It is unordered and it contains only unique elements.

We can create a frozen set using frozenset() function and pass anyone iterable element in this function.

We can use the frozen set in the dictionary as a key because the frozen set is hashable.

Syntax –

frozenset(iterable)

Parameter –

iterable → any iterable element e.g. list, tuple, set, dictionary, string.

return → it returns a frozen set object.

Example –

				
					s = [1,2,3,4,5]
fs = frozenset(s)
print("Frozen set:", fs)
print(type(fs))

# Output -
# Frozen set: frozenset({1, 2, 3, 4, 5})
# <class 'frozenset'>

In the above example ,first we create a list with elements from 1 to 5.

after creating the list, we create a frozen set of list(s) and store the frozen set object in fs.

finally, print the frozen set object on the output screen and also print the type of fs.

Example 2 – Frozen set using a dictionary

				
					d = {'firstname':'edSlash','lastname':'Services'}
frozen_set = frozenset(d)
print("Frozen set: ", frozen_set)

# Output -
# Frozen set:  frozenset({'lastname', 'firstname'})

Let’s try to modify the frozen set –

				
					f_set = frozenset('edSlash')
print("Frozen set: ", f_set)
print("\n\n")
f_Set.remove('s')
print(f_set)

# Output -
# Frozen set:  frozenset({'a', 's', 'h', 'S', 'd', 'l', 'e'})

#Traceback (most recent call last):
#  File "/home/main.py", line 4, in <module>
#    f_Set.remove('s')
#NameError: name 'f_Set' is not defined. Did you mean: 'f_set'?

Accessing elements of Frozen set –

				
					l = [1,2,3,4,5,6]
f_set = frozenset(l)
print("Frozen set: ", f_set)
print("\n\nElements of frozen set: ")
for i in f_set:
	print(i)

# Output -
# Frozen set:  frozenset({1, 2, 3, 4, 5, 6})

# Elements of frozen set: 
# 1
# 2
# 3 
# 4
# 5
# 6

Operations on frozen set –

				
					fs1 = frozenset('edSlash')
fs2 = frozenset('official')
print("Frozen set 1: ", fs1)
print("Frozen set 2: ", fs2)

print("\nNumber of elements in frozen set: ",len(fs1))

# Creating a copy of frozen set
fs1_copy = fs1.copy()
print("\nCopied frozen set:",fs1_copy)

# Union of two frozen sets
fs_union = fs1.union(fs2)
print("\nUnion set:",fs_union)

# Intersection of two frozen sets 
fs_intersection = fs1.intersection(fs2)
print("\nIntersection set:",fs_intersection)

# Difference of two frozen sets
fs_difference = fs1.difference(fs2)
print("\nDifference set:",fs_difference)

# Symmetric difference of two frozen sets
fs_symmetric_difference = fs1.symmetric_difference(fs2)
print("\nSymmetric Difference set: ",fs_symmetric_difference)


# Output -
# Frozen set 1:  frozenset({'e', 'h', 'S', 'd', 'a', 'l', 's'})
# Frozen set 2:  frozenset({'o', 'a', 'i', 'c', 'l', 'f'})
# Number of elements in frozen set:  7
# Copied frozen set: frozenset({'e', 'h', 'S', 'd', 'a', 'l', 's'})
# Union set: frozenset({'o', 'e', 'h', 'S', 'd', 'a', 'i', 'c', 'l', 's', 'f'})
# Intersection set: frozenset({'l', 'a'})
# Difference set: frozenset({'e', 'h', 'S', 'd', 's'})
# Symmetric Difference set:  frozenset({'i', 'f', 'o', 'e', 'h', 'S', 'd', 'c', 's'})

In the above example, we cover a few examples of the frozen set operations you can also perform more operations.

You can perform all operations of set on frozen set except that operation that modifies the frozen set itself e.g. update(), remove(), etc.

Difference between Frozen set and Set –

Frozen set	Set
It is immutable	It is mutable
It is created using `frozenset()` function	It is created using `{}` curly braces or `set()` function.
It is hashable	It is non hashable
Supports operations that do not modify the frozen set	Supports operations that modify the original set

Python

Frozen set in Python

Frozen set in Python

Difference between Frozen set and Set –

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