Python Sets

Python - Sets:

A set is an unordered collection of unique elements. Sets are mutable, which means you can modify them after creation. Sets are denoted by curly braces '{}', and elements are separated by commas.

Creating Sets:

Sets can be created using curly braces '{}' or the set '()' function:

# Creating a set using curly braces
my_set = {1, 2, 3, 4, 5}

# Creating a set using the set() function
another_set = set([6, 7, 8, 9, 10])

Operations on Sets:

Sets support various operations like union, intersection, difference, and symmetric difference:

⤏ Union ('|'): Combines elements from two sets.

⤏ Intersection ('&'): Returns elements common to both sets.

⤏ Difference ('-'): Returns elements in the first set but not in the second set.

⤏ Symmetric Difference ('^'): Returns elements that are in either of the sets, but not in both.

set1 = {1, 2, 3}
set2 = {3, 4, 5}

union_set = set1 | set2  # {1, 2, 3, 4, 5}
intersection_set = set1 & set2  # {3}
difference_set = set1 - set2  # {1, 2}
symmetric_difference_set = set1 ^ set2  # {1, 2, 4, 5}

Modifying Sets:

Sets are mutable, meaning you can add and remove elements:

my_set = {1, 2, 3}

# Adding elements
my_set.add(4)
my_set.update([5, 6])

# Removing elements
my_set.remove(3)
my_set.discard(2)

⤏ Membership Test: Check if an element exists in the set.

⤏ Length: Get the number of elements in a set.

my_set = {1, 2, 3, 4, 5}

# Membership test
print(3 in my_set)  # True

# Length of the set
print(len(my_set))  # 5

Let's create a simple Python program that demonstrates the use of sets.

def main():
    # Create two sets of numbers
    set1 = {1, 2, 3, 4, 5}
    set2 = {4, 5, 6, 7, 8}

    # Perform set operations
    union_set = set1 | set2
    intersection_set = set1 & set2
    difference_set1 = set1 - set2
    difference_set2 = set2 - set1
    symmetric_difference_set = set1 ^ set2

    # Print the results
    print("Set 1:", set1)
    print("Set 2:", set2)
    print("Union:", union_set)
    print("Intersection:", intersection_set)
    print("Difference (Set 1 - Set 2):", difference_set1)
    print("Difference (Set 2 - Set 1):", difference_set2)
    print("Symmetric Difference:", symmetric_difference_set)

if __name__ == "__main__":
    main()

Set 1: {1, 2, 3, 4, 5}
Set 2: {4, 5, 6, 7, 8}
Union: {1, 2, 3, 4, 5, 6, 7, 8}
Intersection: {4, 5}
Difference (Set 1 - Set 2): {1, 2, 3}   
Difference (Set 2 - Set 1): {8, 6, 7}   
Symmetric Difference: {1, 2, 3, 6, 7, 8}

This program defines a 'main()' function where we create two sets, 'set1' and 'set2'. We then perform various set operations and print the results. Finally, we call the 'main()' function to execute the program.

• Sets are useful when you need to work with unique elements and perform operations like finding intersections or differences between collections.