'''lecture_34_dictionaries.py
Showcase what dictionaries are and how to work with them
Oliver W. Layton
CS 151: Computational Thinking: Visual Media
Fall 2020
'''

'''Dictionaries
Works like a physical dictionary or address book:
    you look up a definition ("value") using a WORD ("key")
Different from a list where you look up a value using an INDEX.
'''
# Make a new empty dictionary

# Make a new dictionary with some initial data
# Words (keys): 'grades', 'gpa', 'school'
# Definitions (values): [26, 27, 26], 3.8, 'Colby'


'''Accessing keys and values'''
# You can access the keys and values from the dictionary

# You can convert the keys and values into ordinary lists

# You can loop through keys or values (without converting to lists first)
# Example, loop through keys and values, append each to a list
# keys = []
# values = []

# print(keys)
# print(values)

'''Modifying/adding to a dictionary'''
# Examples: set school to Colby College, add a grade, add a key for dorm

'''Adding to a dictionary via string variables'''
# Example: names-to-GPA lists:
# names = ['Bill', 'Carol', 'Ben']
# gpas = [4, 3.8, 3.6]

'''Checking if a key is in the dictionary'''
# Program will crash if you try to access a key that doesn't exist, so it is a good idea to check
# for it before accessing