Python Set | update()
Python update() function in set adds elements from a set (passed as an argument) to the set.
Syntax : set1.update(set2)
Here set1 is the set in which set2 will be added.
Parameters : Update() method takes only a single argument. The single argument can be a set, list, tuples or a dictionary. It automatically converts into a set and adds to the set.
Return value : This method adds set2 to set1 and returns nothing.
Example of Python set update()
Example 1: Working with Python set update list
# Python program to demonstrate the
# use of update() method
list1 = [1, 2, 3]
list2 = [5, 6, 7]
list3 = [10, 11, 12]
# Lists converted to sets
set1 = set(list2)
set2 = set(list1)
# Update method
set1.update(set2)
# Print the updated set
print(set1)
# List is passed as an parameter which
# gets automatically converted to a set
set1.update(list3)
print(set1)
输出：
{1, 2, 3, 5, 6, 7}
{1, 2, 3, 5, 6, 7, 10, 11, 12}
Example 2: Python set update element in set
# Python program to demonstrate the
# use of update() method
list1 = [1, 2, 3, 4]
list2 = [1, 4, 2, 3, 5]
alphabet_set = {'a', 'b', 'c'}
# lists converted to sets
set1 = set(list2)
set2 = set(list1)
# Update method
set1.update(set2)
# Print the updated set
print(set1)
set1.update(alphabet_set)
print(set1)
输出：
{1, 2, 3, 4, 5}
{1, 2, 3, 4, 5, 'c', 'b', 'a'}
Example 3: Add elements of the dictionary to Set
number = {1, 2, 3, 4, 5}
num_Dict = {6: 'Six', 7: 'Seven', 8: 'Eight',
9: 'Nine', 10: 'Ten'}
number.update(num_Dict)
print("Updated set: ", number)
输出：
Updated set: {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
