Python Sets
Python Set is a collection of items.
Python Set is Unordered
There is no order in which the items are stored in a Set. We cannot access items in a Set based on index.
Python Set has Unique Items
Python Set can store only unique items. We cannot add an item that is already present in the Set.
Python Set is Mutable
We can modify a Set. In other words, we can add items to a Set or remove items from a Set.
Create Python Set
To create a Set in Python, use curly braces {} as shown in the following example.
set_1 = {item_1, item_2, item_3} Place as many items as required inside curly braces and assign it to a variable.
We can also use set() builtin function to create a Python Set. Pass an iterable to the set() function, and the function returns a Set created from the items in that iterable.
set_1 = set(iterable)
Example
In the following program, we create two sets: set_1 and set_2 using curly braces and set() function respectively.
Python Program
#create set using curly braces
set_1 = {2, 4, 6}
print(set_1)
#create set using set() builtin function
set_2 = set({'a', 'b', 'c'})
print(set_2) Try Online Output
{2, 4, 6}
{'b', 'c', 'a'} Access Items of Python Set
Python Set is an iterable. Therefore, we can access items in a Set using for loop or while loop.
Example
In the following program, we create a set with three items, and print items one at a time by accessing them using for loop.
Python Program
set_1 = {2, 4, 6}
for item in set_1:
print(item) Try Online Output
2 4 6
Add Items to Python Set
To add an item to a Python Set, call add() method on the set, and pass the item.
Example
In the following program, we create an empty set, and add three items to it using add() method.
Python Program
set_1 = set() set_1.add(2) set_1.add(4) set_1.add(6) print(set_1)Try Online
Output
{2, 4, 6} Remove Items from Python Set
To remove an item from a Python Set, call remove() method on the set, and pass the item.
Example
In the following program, we create a set with three items, and delete two of them using remove() method.
Python Program
set_1 = set({2, 4, 6})
print(f'Set before removing: {set_1}')
set_1.remove(2)
set_1.remove(6)
print(f'Set after removing: {set_1}') Try Online Output
Set before removing: {2, 4, 6}
Set after removing: {4} Conclusion
In this Python Tutorial, we learned what Python Sets are, how to create them, how to add elements to a set, how to remove elements from a set, and methods of Python Set.