The set data type represents a collection of unordered, unique elements.

Sets are mutable meaning that they can be modified by adding, removing, or replacing elements.

The add() method is used  to add a single element to a set. 

Syntax:
myset.add(e)
e The element to be added to the set.

The add() methods adds element e to the set. There will be no effect if the element is already present.

ExampleEdit & Run
myset = {'Python', 'Java', 'C++'}

#add elements to the set
myset.add('PHP')
myset.add('HTML')
myset.add('Javascript')

print(myset)
 Visualize 
Output:

add() vs update()

If we want to add multiple elements to a set, we may use the add() method with a for loop as follows.

ExampleEdit & Run
myset = {'Python', 'Java', 'C++'}

elements = ['PHP', 'HTML', 'Javascript']

#add the elements to the set
for e in elements:
    myset.add(e)

print(myset)
 Visualize 
Output:
{'PHP', 'Java', 'C++', 'Python', 'Javascript', 'HTML'}

[Finished in 0.029523971000003257s]

However, the set class also contains the update()  methods which   allows you to add multiple elements to a set simultaneously. This approach is more convenient than adding each element individually via a loop.

ExampleEdit & Run
myset = {'Python', 'Java', 'C++'}

elements = ['PHP', 'HTML', 'Javascript']

#use update() to add elements to the set
myset.update(elements)

print(myset)
 Visualize 
Output:
{'HTML', 'C++', 'PHP', 'Python', 'Java', 'Javascript'}

[Finished in 0.012776419000005035s]