How is everybody doing traceback


after adding

print get_class_average(students)
print get_letter_grade(students)

i get the Error:
Traceback (most recent call last):
File "python", line 50, in
File "python", line 46, in get_class_average
File "python", line 27, in get_average
TypeError: list indices must be integers, not str
Oops, try again. One of the following is missing or broken when we tried to use it: alice, lloyd, tyler, students, get_class_average, get_letter_grade

didn´t expect an error in previous lines

lloyd = {
    "name": "Lloyd",
    "homework": [90.0, 97.0, 75.0, 92.0],
    "quizzes": [88.0, 40.0, 94.0],
    "tests": [75.0, 90.0]
alice = {
    "name": "Alice",
    "homework": [100.0, 92.0, 98.0, 100.0],
    "quizzes": [82.0, 83.0, 91.0],
    "tests": [89.0, 97.0]
tyler = {
    "name": "Tyler",
    "homework": [0.0, 87.0, 75.0, 22.0],
    "quizzes": [0.0, 75.0, 78.0],
    "tests": [100.0, 100.0]

students = [lloyd, alice, tyler]
# Add your function below!
def average(numbers):
    total = float(sum(numbers)) / len(numbers)
    return total
def get_average(student):
    homework = average(student["homework"])
    quizzes = average(student["quizzes"])
    tests = average(student["tests"])
    return  0.1 * homework + 0.3 * quizzes + 0.6 * tests 
def get_letter_grade(score):
    if score >= 90:
        return "A"
    elif score >= 80:
        return "B"
    elif score >= 70:
        return "C"
    elif score >= 60:
        return "D"
        return "F"

def get_class_average(students):
    results =[]
    return average(results)

print get_class_average(students)
print get_letter_grade(students)


in your get_class_average function:


you call get_average, with argument students. But get_average is only designed to handle a single student, not a list, which is why you should have a loop? You build the loop (or should have had) in the previous exercise

and here:

print get_letter_grade(students)

get_letter_grade is only designed to convert an integer to a letter grade, so you will first need to calculate the class grade average, and then convert this class grade average into a class letter grade


hum alright, now i am confused,

i get why it has to be results.append(get_average(student)) ( but i get a new NameError: global name 'student' is not defined now )

i don´t get the second part at all, get_glass_average calculates the the average grade of the class

so it has to be print get_letter_grade(get_class_average) ?
or print get_letter_grade(get_class_average(students)) ? or print get_letter_grade(get_class_average(student)) ? because none of these works^^


this only works if you loop over each student in students, did you include the loop? Maybe revisit the previous exercise?

it should be this one:

print get_letter_grade(get_class_average(students))

you calculate the class average for the class, then convert that into letter grade

of course, the condition for this to work you get_class_average function needs to be correct


def get_class_average(students):
results =[]
for student in students:
return average(results)

i had that for loop in lesson 8, now it was missing... weird..

anyways a big thank you



that is weird, but good that you solved it :slight_smile: