TypeError: list indices must be integers, not str


#1



https://www.codecademy.com/en/courses/python-beginner-en-qzsCL/1/5?curriculum_id=4f89dab3d788890003000096

Oops, try again. Did you remember to print the letter grade for the class's average?

Traceback (most recent call last):
File "python", line 55, in <module
File "python", line 30, in get_average
TypeError: list indices must be integers, not str

Stuck here...Dont know what happened
I've already add
students = [lloyd,alice,tyler]...


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]
}

# Add your function below!
# The students's averages!
students = [lloyd,alice,tyler]
def average(numbers):
    total = sum(numbers)
    total = float(total)
    result = total/len(numbers)
    return result

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
# The letter grade that student should receive.
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"
    else:
        return "F"
    print get_letter_grade(get_average(lloyd))
# Now let's calculate the class average.
def get_class_average(students):
    result = []
    for student in students:
        result.append(get_average(student))
    return average(result)
    
print get_class_average(students)
print get_letter_grade(get_average(students))


#2

here:

print get_letter_grade(get_average(students))

get_average is not designed to handle a list of students, get_average() can only handle a single student.

Which function do we have that can handle a list? (the list representing a class with students)


#3

thx!

replace
get_letter_grade(get_average(students))
with this
get_letter_grade(get_class_average(students))

it works~


#4

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