Identifying and Correcting Errors (Unit 1.4)

Become familiar with types of errors and strategies to fixing them

Lightly Review Videos and take notes on topics with Blog

Complete assigned MCQ questions

Here are some code segments you can practice fixing:

alphabet = "abcdefghijklmnopqrstuvwxyz"

alphabetList = []

for i in alphabet:
    alphabetList.append(i)

print(alphabetList)

['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']

The intended outcome is to determine where the letter is in the alphabet using a while loop

What is a good test case to check the current outcome? Why?
Make changes to get the intended outcome.

letter = input("What letter would you like to check?")

i = 0

while i < 26:
    if alphabetList[i] == letter:
        print("The letter " + letter + " is the " + str(i+1) + " letter in the alphabet")
    i += 1

# the count was off due to computer counting, so we added +1 to the string

The letter c is the 3 letter in the alphabet

The intended outcome is to determine where the letter is in the alphabet using a for loop

What is a good test case to check the current outcome? Why?
Make changes to get the intended outcome.

letter = input("What letter would you like to check?")

count = 1

for i in alphabetList:
    if i == letter:
        print("The letter " + letter + " is the " + str(count) + " letter in the alphabet")
    count += 1

# the count variable was defined in the loop, but was moved out of the loop
# the count was also off so we defined count =1 and not 0

The letter z is the 26 letter in the alphabet

This code outputs the even numbers from 0 - 10 using a while loop.

Analyze this code to determine what can be changed to get the outcome to be odd numbers. (Code block below)

evens = []
i = 0

while i <= 10:
    evens.append(i)
    i += 2

print(evens)

[0, 2, 4, 6, 8, 10]

This code should output the odd numbers from 0 - 10 using a while loop.

odds = []
i = 1

while i <= 10:
    odds.append(i)
    i += 2

print(odds)

#this was printing the evens still, so we had to set i=1 not 0

[1, 3, 5, 7, 9]

This code outputs the even numbers from 0 - 10 using a for loop.

Analyze this code to determine what can be changed to get the outcome to be odd numbers. (Code block below)

numbers = [0,1,2,3,4,5,6,7,8,9,10]
evens = []

for i in numbers:
    if (numbers[i] % 2 == 0):
        evens.append(numbers[i])

print(evens)

[0, 2, 4, 6, 8, 10]

This code should output the odd numbers from 0 - 10 using a for loop.

numbers = [0,1,2,3,4,5,6,7,8,9,10]
odds = []

for i in numbers:
    if (numbers[i] % 2 == 1):
        odds.append(numbers[i])

print(odds)

# changed the remainder from 0 to 1

[1, 3, 5, 7, 9]

The intended outcome is printing a number between 1 and 100 once, if it is a multiple of 2 or 5

What values are outputted incorrectly. Why?
Make changes to get the intended outcome.

numbers = []
newNumbers = []
i = 0

while i < 100:
    numbers.append(i)
    i += 1

for i in numbers:
    if numbers[i] == 0:
        pass
    elif numbers[i] % 5 == 0:
        newNumbers.append(numbers[i])
    elif numbers[i] % 2 == 0:
        newNumbers.append(numbers[i])

print(newNumbers) 

#change second if statement to elif to get rid of repeats (else if)
#to get rid of zero, add either continue, or add pass and add elif= if the number is zero it skips

[2, 4, 5, 6, 8, 10, 12, 14, 15, 16, 18, 20, 22, 24, 25, 26, 28, 30, 32, 34, 35, 36, 38, 40, 42, 44, 45, 46, 48, 50, 52, 54, 55, 56, 58, 60, 62, 64, 65, 66, 68, 70, 72, 74, 75, 76, 78, 80, 82, 84, 85, 86, 88, 90, 92, 94, 95, 96, 98]

Challenge

This code segment is at a very early stage of implementation.

What are some ways to (user) error proof this code?
The code should be able to calculate the cost of the meal of the user

Hint:

write a “single” test describing an expectation of the program of the program
test - input burger, expect output of burger price
run the test, which should fail because the program lacks that feature
write “just enough” code, the simplest possible, to make the test pass

Then repeat this process until you get program working like you want it to work.

menu =  {"burger": 3.99,
         "fries": 1.99,
         "drink": 0.99}
total = 0
wholeordertotal = 0


#shows the user the menu and prompts them to select an item
print("Menu")
for k,v in menu.items():
    print(k + "  $" + str(v)) #why does v have "str" in front of it?
    
#ideally the code should prompt the user multiple times
item = input("Please select an item from the menu")

#below the total is = to the value of the item typed in
total = menu[item]

#below is the total for someone who orders the whole menu
for k in menu:
    wholeordertotal = wholeordertotal + menu[k]

#code should add the price of the menu items selected by the user 
print("You owe: $", total)
print("Do you want everything?: $", wholeordertotal)

Menu
burger  $3.99
fries  $1.99
drink  $0.99
You owe: $ 3.99
Do you want everything?: $ 6.970000000000001

Adding up the total with multiple items:

from ast import While


menu =  {"burger": 3.99,
         "fries": 1.99,
         "drink": 0.99}
total = 0


#shows the user the menu and prompts them to select an item
print("Menu")
for k,v in menu.items():
    print(k + "  $" + str(v)) #why does v have "str" in front of it?

#this definition of item is temporary and is just used to item is defined before the function
item = "temporary value"    

while item != "": #!= means not equal to
    #this code prompts the user multiple times until they simply click enter without an input
    item = input("Please select an item from the menu")
    if item !="":
        total = total + menu[item] #this adds up the total of the previous item(s) and the new item

        #this loop will continue until the user enters with no input



#code should add the price of the menu items selected by the user 
print("You owe: $", total)

Menu
burger  $3.99
fries  $1.99
drink  $0.99
You owe: $ 5.98