Please help - why is this giving me the wrong answer?


#1



Stuck on this Student becomes the teacher exercise and I cannot see where I've gone wrong, any help appreciated.
This is what I'm supposed to be doing:
"Define a function called get_class_average that has one argument students. You can expect students to be a list containing your three students.
First, make an empty list called results.
For each student item in the class list, calculate get_average(student) and then call results.append() with that result.
Finally, return the result of calling average() with results."

And this is what I get returned:
"Oops, try again. get_class_average([alice]) returned 83.8666666667 instead of 91.15 as expected"


Any ideas why? Here's my code below:


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]
}

class_list = [lloyd, alice, tyler]
# Add your function below!
def average(numbers): 
    total = float(sum(numbers))
    return total / len(numbers)

def get_average(student):
    homework = average(student["homework"])
    quizzes = average(student["quizzes"])
    tests = average(student["tests"])
    return (homework * 0.1) + (quizzes * 0.3) + (tests * 0.6)
    
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"
        
        
def get_class_average(student):
    results = []
    for student in class_list:
        results.append(get_average(student))
    return average(results)


#2

here:

for student in class_list:

you shouldn't loop over class_list, this way your function only works for one list. Your function should should work for a class of any size (1, 2 or 3 students)

and if you are looping over class_list, why does your function have a parameter (students) which you don't use?


#3

I still don't really understand why it didn't work. When I changed 'class_list' to 'students' and amended the last bit of code to:

def get_class_average(student):
    results = []
    for student in students:
        results.append(get_average(student))
    return average(results)"

it all of a sudden worked fine to have it loop over that list...


#4

well, if we add function calls now:

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

print get_class_average([lloyd])
print get_class_average([lloyd, alice])
print get_class_average([lloyd, alice, tyler])

now your function works for a class of any size, before it only work for a class of 3 students


#5

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