Where is the problem, looks identical!


#1

Hi,

I have two codes, both logically are the same and to some extent written the same but one works and the other doesn't, i just want to understand why doesn't mine work, i know I'm writing it a bit different (we all do) but it should work. any help please?

the issue is not in the indentation.

MyCode (it didn't work):_

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]

def average(numbers):
    total = float(sum(numbers))
    result = total / len(numbers)
    return result 
    
def get_average(student):
    homework = average(student["homework"])
    quizzes = average(student["quizzes"])
    tests = average(student["tests"])
    total = (homework*.1) + (quizzes*.3)+(tests * .6)
    
    return total
    
def get_letter_grade(score):
    score = int(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(students):
    results=[]
    for student in students:
        i=get_average(student)
        results = results.append(i)
        print results
       
print get_class_average(students)
print get_letter_grade(get_class_average(students))

TheSecond_Code_ (it worked) :_

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, tyler, alice]

def average(numbers):
    return float(sum(numbers))/len(numbers)
 
def get_average(student):
    homework = average(student["homework"]) * .1
    quizzes = average(student["quizzes"]) * .3
    tests = average(student["tests"]) * .6
   
    return homework + quizzes + 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"
    else:
        return "F"
       
def get_class_average(students):
    results = []
    for i in students:
        results.append(get_average(i))
    return average(results)
   
print get_class_average(students)
print get_letter_grade(get_class_average(students))

#2

in your first code, your get_class_average doesn't return the average result


#3

understood, but why? where is the problem with the code?


#4

because of what i just said? the exercise expects get_class_average to return the average() of result.

you do this in your second code, but not in your first


#5

I just updated it to return the average as such :

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

Still not working, here is the error : :frowning:

Traceback (most recent call last):
File "/Users/Documents/workbench.py", line 56, in
print get_class_average(students)
File "/Users/Documents/workbench.py", line 54, in get_class_average
return average(results)
File "/Users/Documents/workbench.py", line 23, in average
total = float(sum(numbers))
TypeError: 'NoneType' object is not iterable


#6

append() will update the list for you, so all you have to is:

results.append(i)

because append will update the list for you, you don't need update the variable as well.

also, a function ends the moment a return keyword is reached, this currently happens in the first iteration of your loop. You might want to change the indent of return so the whole for loop can run


#7

not sure why, but the return was for the entire "For statement", and it was on the script too, but seems like when i copied and pasted i messed it up.

However, for some reason, when i removed the results variable and left the results.append(i) as is, it is working working now!

you are awesome man, thank you for taking the time to explain!


#8