Sets

Overview

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Objectives

• Understand how sets work in python

What are sets?

A set is a collection which is unordered and unindexed.

Creating a set:

Sets are created using curly brackets.

set_example={"Digital","Scholorship","Hub",2}
print(set_example)

Remember-

Set items are -

• unordered: We cannot be sure which order the element are stored and displayed in.
• unchangeable: We cannot update the elements of the set. However, we can insert and delete values.
• No duplicate values: Sets cannot have two items with the same value.

Length of a Set:

We use the len() funtion to get the length of the set

print(len(set_example))

The set() Constructor:

The set constructor is used to create a set.

set_constructor=set(("Digital","Scholorship","Hub",2))
print(set_constructor)

Inserting elements into a set:

To insert a single element into an existing set, the add method is used.

set_example.add("Python")
print(set_example)

Instead of a single element, if you want to append another set or any other iterable object(tuples, lists, dictionaries), we can use the update method

list_a=["Beginners","Workshop"]
set_example.update(list_a)
print(set_example)

Deletion of sets:

To delete an element in a set, we use the remove and discard methods.

set_example.remove("Beginners")
set_example.discard("Workshop")

the key difference between these two methods is that remove raises an error if the item to remove does not exist, where as discard does not raise an error.

clear(): This methid will empty the set

set_example.clear()

del: this keyword is used to delete the set completely:

del set_example

Applications of sets

• to enforce uniqueness(like employee ID, Passport number)
• Join Operations

Key Points