🐍 Python Dictionaries (Key-Value Pairs) 🔑

Dictionaries are unordered collections of data that store items in key-value pairs. They are incredibly powerful for organizing and quickly accessing related information.

👉 Ideal for representing real-world objects with unique identifiers (keys).

🔹 1. What is a Dictionary?

A mutable, unordered collection where each item has a unique key and an associated value. Defined by curly braces {}.

Example:

person = {"name": "Alice", "age": 30, "city": "New York"}
print(person)

Output: {'name': 'Alice', 'age': 30, 'city': 'New York'}

🔹 2. Accessing Dictionary Items

Access values using their associated key inside square brackets [] or with the .get() method.

Example:

student = {"id": 101, "name": "Bob", "grade": "A"}
print(student["name"])
print(student.get("grade"))

Output:
Bob
A

🔹 3. Adding and Modifying Items

To add a new item, assign a value to a new key. To modify, assign a new value to an existing key.

Example:

car = {"brand": "Ford", "model": "Mustang"}
car["year"] = 2020 # Add new item
car["model"] = "Explorer" # Modify existing item
print(car)

Output: {'brand': 'Ford', 'model': 'Explorer', 'year': 2020}

🔹 4. Removing Items

• del dict[key]: Removes the item with the specified key.
• .pop(key): Removes (and returns) the item with the specified key.
• .clear(): Empties the entire dictionary.

Example:

settings = {"theme": "dark", "sound": "on", "notifications": "off"}
del settings["sound"] # Remove by key
print(settings)
settings.pop("theme") # Also removes by key
print(settings)

Output:
{'theme': 'dark', 'notifications': 'off'}
{'notifications': 'off'}

🔹 5. Looping Through a Dictionary

You can loop through keys, values, or both (items).

Example:

for k, v in person.items(): # Loops through key-value pairs
    print(f"{k}: {v}")

Output:
name: Alice
age: 30
city: New York

🎯 Today's Goal(What you should do)

✔️ Understand how dictionaries store data in key-value pairs
✔️ Add, access, modify, and remove dictionary items
✔️ Iterate over keys, values, or items