Python Set

A set is an unordered collection of unique elements. Sets are created by enclosing elements within curly braces {} or by using the set() constructor. Sets automatically eliminate duplicate values, and they are mutable, allowing for adding and removing elements.

How to create a Python set

A Python set can be created using curly braces, with the elements of the set separated by commas. For example, the following code creates a set called set1 with three elements:

set1 = {1, 2, 3}

How to access an element in a Python set

You cannot access an element in a Python set by its index, because the order of the elements is not preserved. However, you can check if an element is in a set using the in operator. For example, the following code checks if the element 2 is in the set set1:

if 2 in set1: print('2 is in the set')

Python Set operations:

A = {1, 2, 3, 4} B = {3, 4, 5, 6} # Union of two sets union_set = A B print(union_set) # Output: {1, 2, 3, 4, 5, 6} # Intersection of two sets intersection_set = A & B print(intersection_set) # Output: {3, 4} # Difference of two sets difference_set = A - B print(difference_set) # Output: {1, 2} # Symmetric difference of two sets symmetric_difference_set = A ^ B print(symmetric_difference_set) # Output: {1, 2, 5, 6}

How to iterate through a Python set

You can iterate through a Python set using a for loop. The for loop will iterate over the elements in the set, and you can access each element using the next() method. For example, the following code iterates through the set set1 and prints each element:

for element in set1: print(element) # Output: # 1 # 2 # 3

Why use Python sets?

Python sets are a powerful data structure that can be used to store a variety of data. They are especially useful for storing data that is unique, such as the names of students in a class, or the countries in the world. Sets are also mutable, which means that they can be changed after they are created. This makes them a flexible data structure that can be used to store data that changes over time.


Sets are valuable for storing and managing collections of unique elements, and they are efficient for testing membership and performing set operations like union, intersection, difference, and symmetric difference. The ability to ensure uniqueness and perform set operations makes sets a powerful data structure for solving various problems in Python.