Python - Join Sets

In Python, a Set is an ordered collection of items. The items may be of different types. However, an item in the set must be an immutable object. It means, we can only include numbers, string and tuples in a set and not lists. Python's set class has different provisions to join set objects.

Using the "|" Operator

The "|" symbol (pipe) is defined as the union operator. It performs the A∪B operation and returns a set of items in A, B or both. Set doesn't allow duplicate items.

s1={1,2,3,4,5}
s2={4,5,6,7,8}
s3 = s1|s2
print (s3)

It will produce the following output −

{1, 2, 3, 4, 5, 6, 7, 8}

Using the union() Method

The set class has union() method that performs the same operation as | operator. It returns a set object that holds all items in both sets, discarding duplicates.

s1={1,2,3,4,5}
s2={4,5,6,7,8}
s3 = s1.union(s2)
print (s3)

Using the update() Method

The update() method also joins the two sets, as the union() method. However it doen't return a new set object. Instead, the elements of second set are added in first, duplicates not allowed.

s1={1,2,3,4,5}
s2={4,5,6,7,8}
s1.update(s2)
print (s1)

Using the unpacking Operator

In Python, the "*" symbol is used as unpacking operator. The unpacking operator internally assign each element in a collection to a separate variable.

s1={1,2,3,4,5}
s2={4,5,6,7,8}
s3 = {*s1, *s2}
print (s3)

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