Today, let's move on to the next topic in the Python Coding Challenge: *Dictionaries & Sets* 🔑🧺 🔹 *What is a Dictionary in Python?* A dictionary is an unordered, mutable collection that stores data in key-value pairs. 🧠 *Example:* student = { "name": "Amit", "age": 21, "course": "Python" } print(student["name"]) # Output: Amit - Keys must be unique and immutable (like strings, numbers). - Values can be anything: strings, numbers, lists, or even other dictionaries. 🧰 *Common Dictionary Methods:* student.get("age") # Returns 21 student.keys() # Returns all keys student.values() # Returns all values student.items() # Returns key-value pairs student["grade"] = "A+" # Adds a new key-value pair 🔹 *What is a Set in Python?* A set is an unordered collection of unique elements. 🧠 *Example* : numbers = {1, 2, 3, 4, 4, 2} print(numbers) # Output: {1, 2, 3, 4} — no duplicates - Sets remove duplicates automatically. - Useful for membership checks, uniqueness, and set operations (union, intersection). ✅ *Real-Life Project: Contact Book using Dictionary* - Build a CLI-based contact book where users can: - Add new contacts (name, phone) - View all contacts - Search by name - Delete a contact 💡 *Python Code:* contacts = {} while True: print("\n1. Add Contact\n2. View All\n3. Search\n4. Delete\n5. Exit") choice = input("Enter choice: ") if choice == '1': name = input("Name: ") phone = input("Phone: ") contacts[name] = phone print("Contact saved!") elif choice == '2': for name, phone in contacts.items(): print(f"{name} : {phone}") elif choice == '3': name = input("Enter name to search: ") if name in contacts: print(f"{name}'s phone: {contacts[name]}") else: print("Contact not found.") elif choice == '4': name = input("Enter name to delete: ") if name in contacts: del contacts[name] print("Deleted successfully.") else: print("No such contact.") elif choice == '5': break else: print("Invalid choice.") *React with ❤️ once you’re ready for the quiz* Python Coding Challenge: https://whatsapp.com/channel/0029VaiM08SDuMRaGKd9Wv0L/1661