📔 Dictionaries in Python

Dictionaries are collections of key-value pairs. Keys must be unique and immutable.

dictionary.py


person = {"name": "Alice", "age": 25}
print(person["name"])  # Output: Alice
person["age"] = 26  # Update value
print(person)  # Output: {'name': 'Alice', 'age': 26}

🧩 Dictionary Operations

Dictionaries support various operations like adding, updating, and removing key-value pairs.

dict_operations.py


# Adding a new key-value pair
person["city"] = "New York"
print(person)  # Output: {'name': 'Alice', 'age': 26, 'city': 'New York'}
 
# Removing a key-value pair
del person["age"]
print(person)  # Output: {'name': 'Alice', 'city': 'New York'}
 
# Checking if a key exists
print("name" in person)  # Output: True
 
# Iterating through keys and values
for key, value in person.items():
    print(f"{key}: {value}")
# Output: name: Alice
#         city: New York

🛠️ Dictionary Methods

dict_methods.py


# Dictionary methods
person = {"name": "Alice", "age": 25}
print(len(person))  # Output: 2 (number of key-value pairs)
print("name" in person)  # Output: True (check key existence)
print(person.get("age"))  # Output: 25 (get value safely by key)
print(person.keys())  # Output: dict_keys(['name', 'age']) # Get all keys
print(person.values())  # Output: dict_values(['Alice', 25]) # Get all values
print(person.items())  # Output: dict_items([('name', 'Alice'), ('age', 25)])  # Get all key-value pairs
# Merging dictionaries
new_info = {"city": "New York", "age": 26}
person.update(new_info)
print(person)  # Output: {'name': 'Alice', 'age': 26, 'city': 'New York'}