Chapter 6

Dictionaries

Def: A collection of key-value pairs. Each key is connect to a value, and you can use a key to access the value associated with that key.
A key can be:

• a number
• a string
• a list
• another dictionary
• any object created in python

A dictionary is wrapped in braces {} and a dynamic structure, thus you can add a new key-value pair at any time.

Dictionaries allow you to connect pieces of related information, can store a limitless amount of information, and model a variety of real-world objects.

Dict. alien example

alien_o = {"color": "green", "points":5}
print(alien_o["color"])
print(alien_o["points"])

Adding New Key-Value pairs

alien_o = {"color": "green", "points":5}
print(alien_o["color"])
print(alien_o["points"])

alien_o["x_position"] = 0
alien_o["y_position"] = 25

print(alien_o)

Modifying Values in Dictionary

alien_o = {"color": "green", "points":5}
print(alien_o["color"])
print(alien_o["points"])

alien_o["x_position"] = 0
alien_o["y_position"] = 25

alien_o["color"] = "blue"

print(alien_o)

Removing key-value pairs

del dict["name_of_key"]

alien_o = {"color": "green", "points":5}
print(alien_o["color"])
print(alien_o["points"])

alien_o["x_position"] = 0
alien_o["y_position"] = 25

alien_o["color"] = "blue"

del alien_o["points"]

print(alien_o)