Sets - codenoteshub.com

► Understanding Sets

Sets are unordered collections of unique elements. They automatically remove duplicates and are perfect for membership testing, removing duplicates, and mathematical set operations.

► Real-World Analogy

Think of sets like a bag of unique marbles:
» If you try to add a marble that’s already in the bag, nothing happens
» You can’t have two identical marbles (no duplicates)
» The order doesn’t matter – you just have a collection of unique items
» You can combine bags (union) or find common marbles (intersection)
» Perfect for answering “Is this marble in the bag?”

► Key Concepts

✓ Unique elements: No duplicates allowed
✓ Unordered: Items have no specific position
✓ Mutable: Can add/remove elements
✓ Fast membership testing: O(1) average time
✓ Mathematical operations: union, intersection, difference

■ Code Examples

# Creating sets
fruits = {"apple", "banana", "orange"}
numbers = {1, 2, 3, 4, 5}
mixed = {"hello", 42, True}

print(fruits)

# Removing duplicates
with_duplicates = &#91;1, 2, 2, 3, 3, 3, 4]
unique = set(with_duplicates)
print(f"Unique: {unique}")

# Adding and removing
fruits.add("mango")
fruits.remove("banana")
print(f"Modified: {fruits}")

# Set operations
set1 = {1, 2, 3, 4}
set2 = {3, 4, 5, 6}

print(f"Union: {set1 | set2}")
print(f"Intersection: {set1 &amp; set2}")
print(f"Difference: {set1 - set2}")

# Membership testing
print(f"Is 3 in set1? {3 in set1}")
print(f"Is 10 in set1? {10 in set1}")

# Creating sets

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

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

mixed = {"hello", 42, True}

print(fruits)

# Removing duplicates

with_duplicates = [1, 2, 2, 3, 3, 3, 4]

unique = set(with_duplicates)

print(f"Unique: {unique}")

# Adding and removing

fruits.add("mango")

fruits.remove("banana")

print(f"Modified: {fruits}")

# Set operations

set1 = {1, 2, 3, 4}

set2 = {3, 4, 5, 6}

print(f"Union: {set1 | set2}")

print(f"Intersection: {set1 & set2}")

print(f"Difference: {set1 - set2}")

# Membership testing

print(f"Is 3 in set1? {3 in set1}")

print(f"Is 10 in set1? {10 in set1}")