HOMEWORK 02: FRUITFUL FUNCTIONS & CONDITIONALS 

HOMEWORK 02: FRUITFUL FUNCTIONS & CONDITIONALS 
Introduction
The goal of this homework is for you to learn the difference between print and return as well as give
you practice with conditionals. Part 1 consists of 4 simple functions and 1 function which uses those
4 functions. Part 2 consists of 2 functions that will test your knowledge of conditionals. You have
been given HW2.py to fill out with instructions in the docstrings. However, below you will find more
detailed information to complete your assignment. Read it thoroughly before you begin. You have
until Thursday, September 7th to complete this assignment.
Print vs Return
Two concepts that may be difficult for beginner programmers to differentiate between are the print
function and the return statement. While it may appear that they do the same thing, it is important to
note that they do not do the same thing. The print function as its name states, is a function just like
round or any other pre-defined and user defined functions. The only purpose for the print function
is to display information to the user. You cannot save what you print. The return statement, on the
other hand, is part of a function definition. All functions have a return statement, whether you explicitly
write one or not; functions that do not explicitly have a return statement always return the value None.
The return statement is useful because it allows you to assign a value to a function, thus allowing
you to either save it for later, use it in a more complex expression, or print it for human consumption.
Important note to remember: print is for the user whereas return is for the program.
HOMEWORK 02: FRUITFUL FUNCTIONS & CONDITIONALS 2
Authors: Erica Chia and Christine Feng | Report Issues: echia3@gatech.edu or christinefeng@gatech.edu
Part 1: Market Place
You’ve just moved into your dorm room and now you need to do some shopping. Using the table
below, write the following functions to help you at the grocery store. NOTE: the list price value is the
usual price of the item; the current price value is how much the store is selling the item for right now.
Item name # in stock List price Current price
“avocado” OUT OF STOCK $1.50 $1
“toothpaste” 5 $2.75 $2.75
“popcorn” 10 $1 $1
“bottled water” 8 $5.50 $4
“phone charger” 1 $15 $12
Function name (1): is_in_stock
Parameters: item (str), quantity (int)
Return value: True or False (bool) or None (NoneType)
Description:
Write a function that determines whether or not the parameter item is in stock. If so, you also need
to check that there are enough of that item in stock to fulfill your order (specified by the parameter
quantity). Return True if these conditions are met, False otherwise. Return None if the item is not
in the table.
Test Cases (not an exhaustive list:
is_in_stock(“avocado”, 3) à False
is_in_stock(“bottled water”, 1) à True
is_in_stock(“popcorn”, 100) à False
is_in_stock(“potato chips”, 5) à None
Function name (2): can_afford
Parameters: item (str), quantity (int), wallet (int)
Return value: True or False (bool) or None (NoneType)
Description:
Write a function that determines whether or not you can afford the parameter item, given the number
of that item you would like to buy (specified by parameter quantity), the amount of money you have
(specified by parameter wallet), and the item’s current price value in the table. You do not need to
consider whether there are enough of the item in stock for this function. Return True if you can afford
this item, False otherwise. Return None if the item is not in the table.
Test Cases (not an exhaustive list:
can_afford(“avocado”, 500, 5) à False
can_afford(“phone charger”, 10, 500) à True
can_afford(“mouthwash”, 1, 20) à None
HOMEWORK 02: FRUITFUL FUNCTIONS & CONDITIONALS 3
Authors: Erica Chia and Christine Feng | Report Issues: echia3@gatech.edu or christinefeng@gatech.edu
Function name (3): is_on_sale
Parameters: item (str)
Return value: True or False (bool) or None (NoneType)
Description:
Write a function that determines whether or not the parameter item is on sale, according to the list
price and current price values for the item in the table. You do not need to consider whether the item
is in stock for this function. Return True if it is on sale, False otherwise. Return None if the item is not
in the table.
Test Cases (not an exhaustive list:
isOnSale(“phone charger”) à True
isOnSale(“toothpaste”) à False
isOnSale(“chocolate bar”) à None
Function name (4): is_cheaper
Parameters: item1 (str), item2 (str)
Return value: 0 (int) or 1 (int) or -1 (int) or None (NoneType)
Description:
Write a function that determines whether item1 is cheaper than item2, based on their current
prices. If item1 is cheaper than item2, return 1. If item1 is more expensive than item2, return -1. If
they are equally-priced, return 0. If either parameter item1 or item2 is invalid (i.e. is not included in
the table), return None.
Notes:
• You do not need to consider whether the items are in stock for this function.
• Item names will always be strings; you are not responsible to account for different spellings
or capitalizations of the items listed above.
• Review the test cases below to confirm edge cases.
Test Cases (not an exhaustive list:
is_cheaper(“popcorn”, “bottled water”) à 1
is_cheaper(“avocado”, “popcorn”) à 0
is_cheaper(“toothpaste”, “floss”) à None
HOMEWORK 02: FRUITFUL FUNCTIONS & CONDITIONALS 4
Authors: Erica Chia and Christine Feng | Report Issues: echia3@gatech.edu or christinefeng@gatech.edu
Part 2: Concert Listing
You come across a concert listing with some of your favorite artists! There are prices for single tickets
and group tickets (in packs of 10), and you want to decide how you can attend as many concerts as
possible with your given budget. The following functions help you achieve that goal.
Taylor Swift Adele Zac Brown Band
Single Tickets $275 $152 $25
Group Tickets(10) $3000 $1500 $200
Function name (1): is_single_cheaper
Parameters: artistName(str)
Return value: boolean
Description:
Write a function that takes in the name of one of the artists from the chart. Decide whether or not it
would be cheaper to buy a single ticket, or to get the group ticket price and divide it amongst 10
people. If it’s cheaper for single tickets, then return True, and if not, then return False. If the artist is
not valid, return None.
Test Cases (not an exhaustive list):
is_single_cheaper("Taylor Swift") à True
is_single_cheaper("Chainsmokers") à None
Function name (2): best_price
Parameters: artistName(str)
Return value: representing the best price the user would pay to attend the artist’s concert (int)
Description: Write a function that takes in the name of one of the artists from the chart. Using the
is_single_cheaper function, determine whether a single ticket or group ticket would be the cheapest,
and then return the price of the ticket as an integer. If the group option ends up being the cheapest,
do not return the full price for the group, but the price once it is divided by 10 people. If the artist is
not valid, return None.
Test Cases (not an exhaustive list):
best_price("Taylor Swift") à 275
best_price("Avicii") à None
Function name (3): all_three
Parameters: None
Return value: representing how much it would cost to attend all three concerts (int)
Description: Write a function that uses the best_price function to determine the best prices of each
of the concerts, sums them all up, and returns the total cost.
HOMEWORK 02: FRUITFUL FUNCTIONS & CONDITIONALS 5
Authors: Erica Chia and Christine Feng | Report Issues: echia3@gatech.edu or christinefeng@gatech.edu
Function name (4): cheapest_concert
Parameters: None
Return value: representing the name of the artist with the cheapest concert (str)
Description: Write a function that uses the best_price function to determine the best prices of each
of the concerts, and then returns the name of the artist with the cheapest concert. You may not
use any built in Python functions.
Function name (5): add_two
Parameters: artist1 (str), artist2 (str)
Return value: representing the cost to go to both concerts (int)
Description: Write a function that takes in two artists from the table above, and calculates how much
it would cost to attend both concerts based on their best prices. Return the total cost.
Function name (6): can_afford_concerts
Parameters: money(int)
Return value: None
Description: Write a function that will be using some of the functions that you have written above.
Based on the money passed in, determine if you can go to all three concerts, only two concerts, or
only the cheapest concert. If you can go to all three, print “I can go to all three!”, if you can only go
to two of any combination, (Taylor Swift and Adele, Adele and Zac Brown Band, etc), then print “I
can only go to two!”, and if you can only go to one concert, print a statement in the format of “I can
only go to one.”. If there is not enough money for any of those options, then print out a statement
that says “Dang it, I can’t go to any concert.”. Note: It’s very important that you print out your answer
EXACTLY as it’s formatted in the instructions.
Test Cases (not an exhaustive list):
can_afford_concerts(5)
Dang it, I can’t go to any concert.
can_afford_concerts(24)
I can only go to one.
HOMEWORK 02: FRUITFUL FUNCTIONS & CONDITIONALS 6
Authors: Erica Chia and Christine Feng | Report Issues: echia3@gatech.edu or christinefeng@gatech.edu
Part 3: Miscellaneous
Function name: what_can_you_do
Parameters: age(int)
Return value: None
Description: Write a function that takes in the age of the user and prints out all the activities they are
able to do based on the table below. If they can’t do any of those activities, print out “Sorry, you’re
not old enough for any of these”.
Age Activity
18 vote
21 party
65 retire
Test Cases (not an exhaustive list):
what_can_you_do(5)
Sorry, you’re not old enough for any of these.
what_can_you_do (68)
You can vote, party, and retire.
Function name: pass_or_fail
Parameters: current_grade (int), final_weight (float), final_score (int)
Return value: final letter grade A, B, C, D, or F (str)
Description: Write a function that will take your current grade in a class, the weight of the final exam
as a decimal between 0 and 1, and the score you got on the final exam to determine what letter grade
you’ll receive using the following formula:
�����_����� = �������_����� ∗ (1 − �����_����ℎ�) + �����_����� ∗ �����_����ℎ�
Use the following ranges for letter grades:
• A: 90-100
• B: 80-89.9999
• C: 70-79.9999
• D: 60-69.9999
• F: 0-59.9999
Test Cases (not an exhaustive list):
pass_or_fail(90, .15, 75) <- B
pass_or_fail(60, .3, 100) <- C
HOMEWORK 02: FRUITFUL FUNCTIONS & CONDITIONALS 7
Authors: Erica Chia and Christine Feng | Report Issues: echia3@gatech.edu or christinefeng@gatech.edu
Grading Rubric
- is_in_stock: 10 points
Passes some test cases: 3/10 Points
Passes all test cases: 10/10 Points
- can_afford: 10 points
Passes some test cases: 3/10 Points
Passes all test cases: 10/10 Points
- is_on_sale: 10 points
Passes some test cases: 3/10 Points
Passes all test cases: 10/10 Points
- is_cheaper: 10 points
Passes some test cases: 3/10 Points
Passes all test cases: 10/10 Points
- is_single_cheaper: 10 points
Passes some test cases: 3/10 Points
Passes all test cases: 10/10 Points
- best_price: 10 points
Passes some test cases: 3/10 Points
Passes all test cases: 10/10 Points
- all_three: 5 points
Correct Value is returned: 5 Points
- cheapest_concert: 10 points
Correct Value is returned: 10 Points
- add_two: 5 points
Passes some test cases: 2/5 Points
Passes all test cases: 5/5 Points
- can_afford_concerts: 10 points
Passes some test cases: 3/10 Points
Passes all test cases: 10/10 Points
- what_can_you_do: 5 points
Passes some test cases: 2/5 Points
Passes all test cases: 5/5 Points
- pass_or_fail: 5 points
Passes some test cases: 2/5 Points
Passes all test cases: 5/5 Points
Provided
The following file(s) have been provided to you.
1. HW2.py
This is the file you will edit and implement. All instructions for what the methods should
do are in the docstrings.
Deliverables
You must submit all of the following file(s). Please make sure the filename matches the filename(s)
below. Be sure you receive the confirmation email from T-Square, and then download your
uploaded files to a new folder and run them.
1. HW2.py