Python Sets, Set Comprehension, and Looping - A Complete Guide with Examples

Article by: Manish Methani

Last Updated: October 5, 2021 at 8:04am IST
3 min 3 sec read

Introduction:

In Python, a set is a collection of unique elements that are unordered and unindexed. This means that you cannot access the elements of a set using an index or a key, but you can iterate through the elements using a loop. In this tutorial, we will cover the basics of Python sets, set comprehension, and looping through sets.

Python Sets:

A set in Python is created using curly braces {} or the set() function. Let's create a set of fruits as an example:

fruits = {"apple", "banana", "cherry"}

We can also use the set() function to create a set:

fruits = set(("apple", "banana", "cherry"))

Notice that we use a double set of parentheses when creating a set using the set() function.

Set Comprehension:

Set comprehension is a concise way to create a set based on some condition or expression. The syntax for set comprehension is similar to list comprehension, but we use curly braces {} instead of square brackets []. Let's create a set of even numbers from 1 to 10 using set comprehension:

even_numbers = {x for x in range(1, 11) if x % 2 == 0}
print(even_numbers)  # Output: {2, 4, 6, 8, 10}

In the above example, we use set comprehension to create a set of even numbers from 1 to 10. We iterate through the range of numbers from 1 to 10, and we only add the number to the set if it is even (x % 2 == 0).

Looping through Sets:

To loop through a set, we can use a for loop. Since sets are unordered, we cannot rely on the order of the elements. Let's loop through the fruits set that we created earlier:

fruits = {"apple", "banana", "cherry"}
for fruit in fruits:
    print(fruit)

Output:

apple
banana
cherry

In the above example, we use a for loop to loop through the fruits set. Since sets are unordered, the order of the elements in the output may vary.

Conclusion:

In this tutorial, we covered the basics of Python sets, set comprehension, and looping through sets. Sets are a useful data structure in Python, especially when we need to store unique elements. Set comprehension is a concise way to create sets based on conditions or expressions. Looping through sets can be done using a for loop, but we cannot rely on the order of the elements since sets are unordered.