🧺 Python Set — Unique, Unordered, Powerful Collection

Introduction 🌟

A set in Python is an unordered collection of **unique** elements. Sets automatically remove duplicates and are optimized for fast membership checking. They are ideal for tasks involving uniqueness, mathematical operations, and filtering.

Note

💡 Sets are defined using curly braces or the set() constructor.

1. Creating Sets 🧱

create_set.py

# Empty set (IMPORTANT: {} is a dict)
empty_set = set()

# Set with values
numbers = {10, 20, 30}

# Set automatically removes duplicates
unique_nums = {1, 2, 2, 3, 3, 4}  # {1, 2, 3, 4}

# Mixed data types
mixed = {10, "apple", 3.5, True}

Note

✔️ Sets do NOT allow duplicates.
✔️ Sets are unordered → No indexing.

2. Accessing Elements ❌➡️✔️

Sets do NOT support indexing like lists or tuples.

access_set.py

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

for item in fruits:
    print(item)

Note

✔️ You can loop through the set to access items.
✔️ Order is NOT guaranteed.

3. Adding Elements ➕

add_set.py

fruits = {"apple", "banana"}
fruits.add("mango")
print(fruits)

4. Adding Multiple Items ➕➕

update_set.py

fruits.update(["grape", "kiwi"])
print(fruits)

5. Removing Elements ➖

remove() — Errors if item not found

remove_set.py

fruits.remove("banana")

discard() — Safe removal

discard_set.py

fruits.discard("orange")  # No error even if 'orange' not found

pop() — Removes a random element

pop_set.py

fruits.pop()

clear() — Remove all elements

clear_set.py

fruits.clear()

6. Set Operations (Most Powerful Feature) ⚡

Union ( | ) — Combine Sets

union_set.py

a = {1, 2, 3}
b = {3, 4, 5}

print(a | b)   # {1, 2, 3, 4, 5}

Intersection ( & ) — Common Elements

intersection_set.py

print(a & b)   # {3}

Difference ( - ) — Items in A not in B

difference_set.py

print(a - b)   # {1, 2}

Symmetric Difference ( ^ ) — Items NOT in both

symmetric_difference.py

print(a ^ b)   # {1, 2, 4, 5}

Note

💡 Set operations are extremely fast due to hashing.

7. Checking Membership 🔍

membership_set.py

nums = {10, 20, 30}

print(20 in nums)        # True
print(25 not in nums)    # True

8. Frozen Set — Immutable Set 🧊

A frozenset is an immutable version of a set. It cannot be changed after creation.

frozenset.py

fs = frozenset([1, 2, 3])
print(fs)

9. Set Comprehension ⚡

set_comprehension.py

squares = {x*x for x in range(1, 6)}
print(squares)

Note

✔️ Similar to list comprehension but produces a set.

10. Real-World Examples 🌍

Removing Duplicates From a List

remove_duplicates.py

nums = [1, 2, 2, 3, 3, 4]
unique = list(set(nums))
print(unique)

Checking Common Interests

common_interests.py

person1 = {"music", "sports", "coding"}
person2 = {"coding", "movies"}

print(person1 & person2)  # intersection

Filtering Unique Words

filter_words.py

sentence = "apple banana apple mango banana"
words = set(sentence.split())
print(words)

Conclusion 🎉

>>“Sets bring speed, uniqueness, and mathematical power to Python — simple yet incredibly useful.” ✨

You now fully understand Python Sets! Want the next topic? Try Dictionary, List Comprehension, Functions, or File Handling. Just tell me! 😊