The syntax of update() is:
A.update(iterable)
Here, A is a set, and iterable can be any iterable such as list, set, dictionary, string, etc. The elements of the iterable are added to the set A.
Let's take another example:
A.update(iter1, iter2, iter3)
Here, the elements of iterables iter1, iter2, and iter3 are added to set A.
Return Value from update()
This set update() method returns None (returns nothing).
Example 1: Python set update()
A = {'a', 'b'}
B = {1, 2, 3}
result = A.update(B)
print('A =', A)
print('result =', result)
Output
A = {'a', 1, 2, 3, 'b'}
result = None
Example 2: Add elements of string and dictionary to Set
string_alphabet = 'abc'
numbers_set = {1, 2}
# add elements of the string to the set
numbers_set.update(string_alphabet)
print('numbers_set =', numbers_set)
info_dictionary = {'key': 1, 'lock' : 2}
numbers_set = {'a', 'b'}
# add keys of dictionary to the set
numbers_set.update(info_dictionary)
print('numbers_set =', numbers_set)
Output
numbers_set = {'c', 1, 2, 'b', 'a'}
numbers_set = {'key', 'b', 'lock', 'a'}
Note: If dictionaries are passed to the update() method, the keys of the dictionaries are added to the set.