Quiz Review

Background

The quiz will be based on the topics covered in weeks 8 through 10. There are 3 sections — short answer questions, Python statements, and a programming problem. Students are allowed to use the Thonny IDE for Section III only. Please see the grading rubric for the programming problem. Scratch paper and a simple calculator are allowed.

Section I (20 points)

1. How many times will the following loop run?

lst = [10, 21, 78, 104, 67]

for x in lst:
    if x > 100:
        break

2. Given:

def main():
    x = 20
    lst = [12, 21, 2]
    lst = func(x, lst)
    print("Value at index 1 is", lst[1])
    print("Value at index 2 is", lst[2])

def func(num1, number_list):
    num1 = 10
    number_list[1] = num1
    number_list[2] = num1 * 3
    return number_list

main()

What will be the output?

3. What will be the result of the following code?

my_list = [1, 2, 3, 4, 5, 6, 7]
print(my_list[3:6])

4. What is the output of the following code?

my_dictionary = {"a": 5, "b": 7}
my_dictionary["c"] = my_dictionary["a"] + my_dictionary["b"]
print(my_dictionary)

5. What will the following code output?

my_list = [10, 20, 30, 40, 50, 60]
print(len(my_list))

6. Why will the following lines of code raise an error?

my_dictionary = {"name": "Alice"}; 
print(my_dictionary[1])

7. What will be the output of the following code?

my_list = [99, 35, 103]
my_list[1] = 42
print(my_list)

8. Which method would you use to get a list of all values in a dictionary?

A. my_dictionary.keys()
B. my_dictionary.values()
C. my_dictionary.items()
D. my_dictionary.get()

9. Write an expression that will correctly update the value of “score” to 92 in the following dictionary.

student = {"name": "Alice", "score": 88, "grade": "B"}

10. Write an expression to add a new key-value pair “subject”: “Math” to the dictionary student.

student = {"name": "Alice", "score": 88, "grade": "B"}

Section II (40 points)

Given the following dictionary and list:

grades = {"Alice": 95, "Brian": 82, "Cathy": 74, "David": 63, "Ella": 88}
numbers = [14, 25, 36, 47, 5, 16]

Write Python statements to do the following:

a. Update the dictionary by adding a new item with the key “Frank” and the value 85.
b. Write a for loop to print each key and its corresponding value in the dictionary.
c. Print the value associated with the key “David”.
d. Update the value for the key “Cathy” to 80.
e. Print the average of the numbers in the numbers list.
f. Get the index location of 47 in the numbers list.
g. Create a list of all the values in the dictionary grades.
h. Find the sum of all the values in the dictionary grades.

Section III (40 points)

Programming question:

You can use the Thonny Python IDE for writing the program.

Write a program that prompts users to enter a sequence of 6 numbers separated by spaces. If the sequence length is not 6, display an appropriate message and exit. Otherwise, create a dictionary that stores the count of numbers above or equal to the average and the count of numbers below the average of the input numbers.

Sample run:

Enter 6 numbers separated by spaces: 25 88 12 42 9 3
{'Above or equal to average': 2, 'Below average': 4}

Solution to the above programming problem:

''' 
Author name: <Your name here>
This program will prompt a user to enter a sequence of 6 numbers separated by spaces.
If the sequence length is not 6, display an appropriate message and exit.
Otherwise, create a dictionary that stores the count of numbers above or equal to
the average and the count of numbers below the average of the input numbers.
'''

# Prompt the user to enter the 6 numbers.
numbers = input("Enter 6 numbers separated by spaces: ")

# Split the number string into individual digits (character strings).
list_of_string_numbers = numbers.split()

# Check to see if the user entered exactly 6 numbers.
# If they did then proceed to process the list of numbers,
# else print an error message.
if len(list_of_string_numbers) == 6:

    # Create a new list to store the integer values after converting from string digits.
    list_of_numbers = []
    
    # For each string version of the numbers in the list.
    for string_num in list_of_string_numbers:
        # Add the number to the list of numbers after converting it to an integer.
        list_of_numbers.append(eval(string_num))
        
    # Calculate the average of the list of numbers.
    average = sum(list_of_numbers) / len(list_of_numbers)
    
    # Create a new dictionary, with two keys.
    # One key is used to store the count of numbers that are above or equal to the average.
    # The other key is used to store the count of numbers that are below average.
    dictionary = {"Above or equal to average":0, "Below average": 0}
    
    # For each number in the list of numbers.
    # Check to see if that number is above or equal to the average. 
    for num in list_of_numbers:
        # If the number is above or equal to the average.
        if num >= average:
            # Increment the count of numbers in the dictionary that are above or equal to the average.
            dictionary["Above or equal to average"] = dictionary["Above or equal to average"] + 1
        else:
            # Else increment the count of numbers that are below average.
            dictionary["Below average"] = dictionary["Below average"] + 1
    
    # Print the dictionary.
    print(dictionary)

else:
    # Print the error message 
    print("You did not enter 6 numbers!")   

Grading Rubric for Section III:

Grading	Points Possible
Appropriate header and comments	5
Input	10
Computation	15
Print output	10