if statements

Question 1

5.1 Write a series of conditional tests. Print a statement describing each test and your prediction for the results of each test

Answer 1

car = ‘subaru’
print(car == ‘subaru’)
print(car == ‘audi’)

Question 2

Write an if statement with one test and one action

Answer 2

if conditional_test:
do something

or

age = 19
if age >= 18:
print(“you are old enough to vote!”)

Question 3

add an else statement to any previous if statement

Answer 3

age = 19
if age >= 18:
print(““you are old enough to vote!””)
Else:
print(“You are too young to vote”)

Question 4

write an if-elif-else chain using -admissions for anyone under the age of 4 is free - admissions for anyone between the ages of 4 and 18 is $25 -admissions for anyone older than 18 is $40

Answer 4

age = 12
if age < 4: 
     price = 0
elif age <18:
     price = 25 
else:
      price = 40

Question 5

add another elif statement with the additions of above 65 = 40.

Answer 5

elif age<65:

price = 20

Question 6

why would you omit the else statement?

Answer 6

if you have a specific final condition you are testing for, it may be appropriate to omit the else

Question 7

test multiple if statements using a list

Answer 7

requested_toppings = [‘mushrooms’, ‘extra cheese’]
If ‘mushrooms’ in requested_toppings:
print(“adding mushrooms”)
if ‘pepperoni’ in requested_toppings:
print(“adding pepperoni”)
if ‘extra cheese’ in requested_topping:
print(“adding extra cheese”)

Question 8

why would you use multiple if statements?

Answer 8

python only needs one test to pass in an if-elif-else chain. Use multiple if it’s possible for more than one condition to be true.

Question 9

write a for loop that prints out a value in a string

Answer 9

requested_toppings = [‘mushrooms’, ‘green peppers’, ‘extra cheese’]
for value in requested_toppings:
print(f”“adding {value}.””)
print(“\nFinished making your pizza”)

Question 10

add an if-else chain to the for loop that says they are out of green peppers

Answer 10

if value == ‘green peppers’:
print(““sorry we are out of green peppers””)
else:
print(f”adding {value}”)

Question 11

Check to make sure a list isn’t empty

Answer 11

if requested_toppings:
for value in requested_toppings:
print(f”adding {value}.”)
print(“\nFinished making your pizza”)
else:
print(“are you sure you want a plain pizza”)

Question 12

Use the pizza example to create multiple lists and check if the items in one list are in the other list . use if-else statement to print out answers if an item is and isn’t in a list

Answer 12

available_toppings = [‘mushrooms’, ‘olives’, ‘pepperoni’, ‘pineapple’,’extra cheese’, ‘green peppers’]

requested_toppings = [‘mushrooms’, ‘french fries’, ‘extra cheese’]
for value in requested_toppings:
if value in available_toppings:
print(f”adding {value} to the pizza.”)
else:
print(f”sorry we don’t have any {value}”)

Question 13

5. 8: make a list of five or more usernames, including the name ‘admin’. imagine you are writing code that will print agreeing to each user after they log into a website. loop through the list and print a greeting to each.
   - if the user is ‘admin’, print a special greeting
   - otherwise print a generic greeting

Answer 13

usernames = [‘eric’, ‘willie’, ‘admin’, ‘erin’, ‘ever’]

for username in usernames:
if username == ‘admin’:
print(“Hello admin, would you like to see a status report?”)
else:
print(f”Hello {username}, thank you for loggin in again!”)

Question 14

5. 9: add an if test to make sure to 5.8 to make sure the list is not empty
   - if the list is empty, print ‘we need to fid some users’
   - finally, clear the list and then make sure the correct message is printed

Answer 14

usernames = []

if usernames:
    for username in usernames:
        if username == 'admin':
            print("Hello admin, would you like to see a status report?")
        else:
            print(f"Hello {username}, thank you for loggin in again!")
else:
    print("We need to find some users!")

Question 15

5.10: Do the following to create a program that simulates how websites ensure that everyone has a unique username.

• Make a list of five or more usernames called current_users.
• Make another list of five usernames called new_users.
• Make sure one or two of the new usernames are also in the current_users list.
• Loop through the new_users list to see if each new username has already been used.
• If it has, print a message that the person will need to enter a new username.
• If a username has not been used, print a message saying that the username is available.
• Make sure your comparison is case insensitive. If ‘John’ has been used, ‘JOHN’ should not be accepted.

Answer 15

current_users = ['eric', 'willie', 'admin', 'erin', 'Ever']
new_users = ['sarah', 'Willie', 'PHIL', 'ever', 'Iona']

current_users_lower = [user.lower() for user in current_users]

for new_user in new_users:
if new_user.lower() in current_users_lower:
print(f”Sorry {new_user}, that name is taken.”)
else:
print(f”Great, {new_user} is still available.”)

Question 16

5.11:Ordinal numbers indicate their position in a list, such as 1st or 2nd. Most ordinal numbers end in th, except 1, 2, and 3.

Store the numbers 1 through 9 in a list.
Loop through the list.
Use an if-elif-else chain inside the loop to print the proper ordinal ending for each number. Your output should read “1st 2nd 3rd 4th 5th 6th 7th 8th 9th”, and each result should be on a separate line.

Answer 16

numbers = list(range(1,10))

for number in numbers:
    if number == 1:
        print("1st")
    elif number == 2:
        print("2nd")
    elif number == 3:
        print("3rd")
    else:
        print(f"{number}th")