Python dictionary

A dictionary allows you to store keys and their values and it is useful when you know the key and you want the value back.

Example:

friend_ages = {"Anne": 30, "Mark": 25, "John": 27}
print(friend_ages["Mark"]) # 25

Adding/changing a value:

friend_ages["Bob"] = 28

Dictionaries keep the order, but like in sets you cannot have duplicates in keys.