The set.add() method in Python adds a single element to a set. It automatically ignores duplicate values and only accepts immutable (hashable) types like numbers, strings and tuples. Mutable types such as lists or dictionaries cannot be added.
Example: In this example, an empty set is created using set() function then an element 's' is added in the empty set 'a' using add() function.
a = set()
a.add('s')
print(a)
Output
{'s'}
Explanation: set() creates an empty set and a.add('s') adds 's' to the set
Syntax
set_name.add(element)
- Parameter: element - The value to be added to the set.
- Returns: It does not return anything (None).
Examples
Example 1: In this example, we add elements to a set of characters and observe that duplicate values are ignored.
a = {'g', 'e', 'k'}
a.add('s')
print(a)
a.add('s')
print(a)
Output
{'g', 'k', 's', 'e'}
{'g', 'k', 's', 'e'}
Explanation: a.add('s') adds 's' to the set and calling a.add('s') again does not change the set.
Example 2: In this example, we add numbers to a set and see how duplicate values are handled.
a = {6, 0, 4}
a.add(1)
print(a)
a.add(0)
print(a)
Output
{0, 1, 4, 6}
{0, 1, 4, 6}
Explanation: a.add(1) inserts 1 into the set and a.add(0) does not change the set because 0 already exists.
Example 3: Here, we add a tuple using add() and multiple elements from a list using update().
s = {'g', 'e', 'e', 'k', 's'}
t = ('f', 'o')
l = ['a', 'e']
s.add(t)
s.update(l)
print(s)
Output
{'k', 's', ('f', 'o'), 'g', 'e', 'a'}
Explanation:
- Duplicate 'e' is removed when creating the set and s.add(t) adds the tuple ('f', 'o') as a single element
- s.update(l) adds elements of list l individually and duplicate 'e' from l is ignored.