Dictionaries in Python

A dictionary in Python stores key-value pairs. Each key maps to a value, like a real dictionary where each word (key) maps to a definition (value).

scores = {"Alice": 95, "Bob": 87, "Charlie": 72}

Dictionaries use curly braces {}. Keys and values are separated by colons :, and pairs are separated by commas.

person = {"name": "Alice", "age": 25, "city": "NYC"}
print(person["name"])  # "Alice"
print(len(person))     # 3

You can add new key-value pairs after creation:

scores = {}
scores["Alice"] = 95
scores["Bob"] = 87