Python TypeError:不支持/：“int”和“NoneType”的操作数类型

Question

问题

我正在做一个可以告诉你成绩的程序。我已经得到了所有的用户输入，现在我需要做一些计算。当调用“计算加权平均数”时，我的问题就出现了。它将参数作为整数（至少我认为是这样的：我要求它print(x, y, z)并打印两次，一次作为x，y，z的正确输入，一次作为x的正确输入，但它不打印y和z作为None），但它拒绝执行我要求它做的数学运算。函数不应该接受参数并执行这个简单的操作：( x + y ) * z？
所以出于某种原因，y和z变成了None，这就是我需要解决的问题！在

代码

def main():
    tests = get_initial_input("tests")
    assignments = get_initial_input("assignments")
    exercises = get_initial_input("exercises")
    labs = get_initial_input("labs")
    finals = get_initial_input("finals")
    testsp = get_percents(tests , "tests")
    assignmentsp = get_percents(assignments, "assignments")
    exercisesp = get_percents(exercises, "exercises")
    labsp = get_percents(labs, "labs")
    finalsp = get_percents(finals, "finals")
    testst = get_totals(tests, "tests")
    assignmentst = get_totals(assignments, "assignments")
    exercisest = get_totals(exercises, "exercises")
    labst = get_totals(labs, "labs")
    finalst = get_totals(finals, "finals")
    testss = get_scores(tests, "tests")
    assignmentss = get_scores(assignments, "assignments")
    exercisess = get_scores(exercises, "exercises")
    labss = get_scores(labs, "labs")
    finalss = get_scores(finals, "finals")
    testsz = calculate_weighted_average(testss, testst, testsp)
    assignmentsz = calculate_weighted_average(assignmentss, assignmentst, assignmentsp)
    exercisesz = calculate_weighted_average(exercisess, exercisest, exercisesp)
    labsz = calculate_weighted_average(labss, labst, labsp)
    finalsz = calculate_weighted_average(finalss, finalst, finalsp)
def get_initial_input(x):
    val = int(input("How many "+ x + " were there?    "))
    return val

def get_percents(x, string):
    if x > 0:
            xp = int(input("What percentage are "+ string + " weighted?       "))
            return xp

def get_totals(x, string):
    if x > 0:
            xt = int(input("How many total points available in the "+ string +" category?      "))
            return xt

def get_scores(x, string):
    total = 0
    for y in range(x):
            xs = int(input("Scores for "+ string +" ?:     "))
            total = total + xs
    return total
def calculate_weighted_average(x, y, z):
    print(x, y, z)
    this = ( x / y ) * z
    return this

main()

回溯

^{pr2}$

提前谢谢您

Answer 1

功能

def get_totals(x, string):
  if x > 0:
        xt = int(input("How many total points available in the "+ string +" category?      "))
        return xt

当x小于或等于零时返回None。此值随后传播到calculate_weighted_average中的数值表达式并将其断开。 修复此函数和其他函数以始终返回数字或引发异常。在