Welcome to this enlightening lesson where we’ll delve into the world of sets in Python. Sets are versatile data structures that provide a unique collection of unordered and distinct elements. In this lesson, we’ll explore the fundamentals of sets, understand their properties, and perform various set operations.
Introduction to Sets:
1. Definition:
- A set is an unordered collection of unique elements.
- Elements in a set are enclosed in curly braces
{}. - Syntax:
my_set = {element1, element2, ...}
2. Creating a Set:
- Sets can be created using the
set()constructor or by enclosing elements in curly braces. - Example:
fruits_set = {"apple", "orange", "banana"}
3. Uniqueness of Elements:
- Sets only contain unique elements; duplicates are automatically removed.
- Example:
colors_set = {"red", "green", "red", "blue"}
Set Operations:
4. Adding Elements:
- Elements can be added to a set using the
add()method. - Example:
my_set = {1, 2, 3}
my_set.add(4)
5. Removing Elements:
- Elements can be removed from a set using the
remove()ordiscard()methods. - Example:
my_set = {1, 2, 3, 4}
my_set.remove(3)
6. Set Operations – Union:
- The union of two sets contains all unique elements from both sets.
- Example:
set1 = {1, 2, 3}
set2 = {3, 4, 5}
union_set = set1.union(set2)
7. Set Operations – Intersection:
- The intersection of two sets contains common elements.
- Example:
set1 = {1, 2, 3}
set2 = {3, 4, 5}
intersection_set = set1.intersection(set2)
8. Set Operations – Difference:
- The difference of two sets contains elements present in the first set but not in the second.
- Example:
set1 = {1, 2, 3}
set2 = {3, 4, 5}
difference_set = set1.difference(set2)
Example:
Let’s consider an example where we use sets to represent different categories of items and perform set operations:
# Example Code
fruits_set = {"apple", "orange", "banana"}
citrus_fruits = {"orange", "lemon", "grapefruit"}
# Adding a new fruit to the set
fruits_set.add("grape")
# Removing a fruit from the set
fruits_set.remove("apple")
# Union of sets
all_fruits = fruits_set.union(citrus_fruits)
# Intersection of sets
common_fruits = fruits_set.intersection(citrus_fruits)
# Difference of sets
non_citrus_fruits = fruits_set.difference(citrus_fruits)
# Displaying the results
print("All Fruits:", all_fruits)
print("Common Fruits:", common_fruits)
print("Non-Citrus Fruits:", non_citrus_fruits)
Practice Exercise:
Create a Python script that uses sets to represent the favorite colors of two individuals. Perform set operations to find the common favorite colors and the unique favorite colors of each individual.
# Example Practice Exercise
person1_colors = {"red", "green", "blue", "yellow"}
person2_colors = {"blue", "orange", "green", "purple"}
# Find common favorite colors
common_colors = person1_colors.intersection(person2_colors)
# Find unique favorite colors of each person
person1_unique_colors = person1_colors.difference(person2_colors)
person2_unique_colors = person2_colors.difference(person1_colors)
# Displaying the results
print("Common Favorite Colors:", common_colors)
print("Person 1 Unique Colors:", person1_unique_colors)
print("Person 2 Unique Colors:", person2_unique_colors)
Summary:
In this lesson, we’ve explored the fundamentals of sets in Python and performed various set operations. Sets provide a convenient way to work with unique collections of elements. Practice using sets to enhance your coding skills, and feel free to ask questions in the discussion forum. Let’s continue our Python journey with confidence in utilizing sets for different scenarios!