Why does my code think I'm comparing a list to an int?-CodePudding

This code is meant to do the following:

Take a value for the number of classes a user is taking
Add grades into a list with the same length as the previously specified classes
Find the average of those values in the list
Output a letter grade equivalent based on that average

This is an assignment for school I'm working on and as a novice user of Python, I wanted some help in trying to figure out where I'm going wrong. When I run this code, I get the following error: "Line 13: TypeError: '>=' not supported between instances of 'list' and 'int'". I'm super curious why I'm getting that error because I don't think I'm passing average over to numToLetterGrade as a list.

I've tried a couple of things involving using a while loop to iterate through each part of the list and add it that way instead of using sum and len but got the same result. I'm also in a situation where I keep seeing the use of for loops, but I haven't officially learned that in class yet and my professor doesn't want me to use code that I haven't used.

Any ideas would be greatly appreciated. Thanks!

def getUserGrades(grades):
    inputsList = list(grades)
    
    return inputsList

def calNumAverage(inputsList):
    gradeAverage = 0
    average = sum(inputsList)/len(inputsList)
    return average

def numToLetterGrade(average):
    letterGrade = " "
    if(average >= 93 and average <= 100):
        letterGrade = "A "
    elif(average >= 90 and average <= 92):
        letterGrade = "A"
    elif(average >= 87 and average <= 89):
        letterGrade = "A-"
    elif(average >= 83 and average <= 86):
        letterGrade = "B "
    elif(average >= 80 and average <= 82):
        letterGrade = "B"
    elif(average >= 70 and average <= 79):
        letterGrade = "C"
    elif(average >= 60 and average <= 69):
        letterGrade = "D"
    else:
        letterGrade = "F"

    return letterGrade
    
def main():
    grades = []
    user1 = int(input("Number of classes :"))
    while(user1 != 0):
        grades.append(float(input("Numeric Grade: ")))
        user1 = user1 - 1
    lists = getUserGrades(grades)
    average1 = numToLetterGrade(lists)
    ltrGrade = average1(numToLetterGrade)
    print("Your average letter grade is: "   ltrGrade)

main()

Example Expected Output:

Number of Classes: 3
Numeric Grade: 85
Numeric Grade: 90
Numeric Grade: 80
Your average letter grade is: B

CodePudding user response：

You actually got the code construct and the solution algorithms right. But you missed some things in the main function, compare the changes here -

def main():
grades = []
user1 = int(input("Number of classes :"))
while(user1 != 0):
    grades.append(float(input("Numeric Grade: ")))
    user1 = user1 - 1
lists = getUserGrades(grades)
average1 = calNumAverage(lists)
ltrGrade = numToLetterGrade(average1)
print("Your average letter grade is: "   ltrGrade)

CodePudding user response：

Here we see you are passing the return value of getUserGrades, a list, to numToLetterGrade, which is expecting an integer value.

lists = getUserGrades(grades)
average1 = numToLetterGrade(lists)
ltrGrade = average1(numToLetterGrade)

You are also trying to call average1 after this as if it were a function, and passing it the numToLetterGrade function as an argument.

Note, getUserGrades is completely superfluous, since grades is already a list.

This example should give you the correct results:

def calNumAverage(inputsList):
    average = sum(inputsList)/len(inputsList)
    return average

def numToLetterGrade(average):
    letterGrade = " "
    if(average >= 93 and average <= 100):
        letterGrade = "A "
    elif(average >= 90 and average <= 92):
        letterGrade = "A"
    elif(average >= 87 and average <= 89):
        letterGrade = "A-"
    elif(average >= 83 and average <= 86):
        letterGrade = "B "
    elif(average >= 80 and average <= 82):
        letterGrade = "B"
    elif(average >= 70 and average <= 79):
        letterGrade = "C"
    elif(average >= 60 and average <= 69):
        letterGrade = "D"
    else:
        letterGrade = "F"

    return letterGrade

def main():
    grades = []
    user1 = int(input("Number of classes :"))
    
    while(user1 != 0):
        grades.append(float(input("Numeric Grade: ")))
        user1 = user1 - 1

    avg = calNumAverage(grades)
    grade = numToLetterGrade(avg)
    print("Your average letter grade is: "   grade)

main()

Cleaned up further:

def average(lst):
    return sum(lst) / len(lst)

def letter_grade(score):
    if   93 <= score <= 100: return "A "
    elif 90 <= score <= 92:  return "A"
    elif 87 <= score <= 89:  return "A-"
    elif 83 <= score <= 86:  return "B "
    elif 80 <= score <= 82:  return "B"
    elif 70 <= score <= 79:  return "C"
    elif 60 <= score <= 69:  return "D"

    return "F"

if __name__ == "__main__":
    classes = int(input("Number of classes: "))
    grades = [float(input("Numeric Grade: ")) for _ in range(classes)]

    print("Your average letter grade is: "   letter_grade(average(grades)))