# CS111: Dictionary Part 1 Solutions

# Task 0. Warm up exercises
# Given this backpack dictionary:
backpack = {
      'money' : 10,
      'pencils' : 4,
      'umbrella' : True,
      'misc': ['lip balm', 'tissues', 'gum']
      }

# Task A: backpack['misc']
# Task B: backpack['misc'].append('calculator')
# Examples of printing options:
#---- Option 1:-----
# In[]: backpack
# Out[5]: 
# {'misc': ['lip balm', 'tissues', 'gum', 'calculator'],
#  'money': 10,
# 'pencils': 4,
# 'snack': 'flaming hot cheetos',
# 'umbrella': True}
#---- Option 2:-----
# 
# print backpack
# {'money': 10, 'snack': 'flaming hot cheetos', 'umbrella': True, 'misc': ['lip# balm', 'tissues', 'gum', 'calculator'], 'pencils': 4}
#
# NOTE: order doesn't matter in dictionaries, so items are not ordered

# Task C: backpack['snack'] = 'flaming hot cheetos'
# Task D: The output looks like this:

# for item in backpack:
#      print item
#     
# money
# snack
# umbrella
# misc
# pencils
#
# When you loop through a dictionary, the KEYS of the dictionary are printed

# Task E: if there is more than $5 in your backpack, subtract 5 to buy a snack
# if backpack['money'] > 5:
#     backpack['money'] -= 5
#
# OR, EQUIVALENTLY, 
#
# if backpack['money'] > 5:
#     backpack['money']  =  backpack['money'] - 5
#
# ............. end warm up exercises ...............

# Task 1. Build the cs111 students names and years
from nameYear import *
from wordlist import *

cs111dict = {}

for person in nameYear:  # person looks like this: ['Kathryn', '2021']
    name = person[0]
    year = person[1]

    cs111dict[name] = year

if __name__ == '__main__':
    print ('\n\n====== test cs111dict =====')
    print (cs111dict)
    print (len(cs111dict)) # 98

# Task 1
def makeYearDict(data):
    """Returns a dictionary where the keys are graduation year (in strings) and the values
    are lists of student names with that graduation year"""
    yearDict = {} # start with an empty dictionary
    for item in data:
        # a sample item ['Jennifer', '2020']
        # so item[0] is 'Jennifer' and item[1] is '2020'
        # check to see if year is already a key in dict
        if item[1] in yearDict:
            # add name to the end of the list of names
            yearDict[item[1]].append(item[0])
        else:
            # create a new key:value pair, where the value is a list containing the name
            yearDict[item[1]] = [item[0]] # very important that this is a LIST
    return yearDict                       # so names can be appended to it later