显示ZeroDivisionError

Question

我使用类创建了这个python脚本，它获取了学生姓名，学号，学生课程和成绩。

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执行后，它成功显示此输出：

#!/usr/bin/env python3

class Student:
    def __init__(self, name, number):
        self.name = name
        self.number = number
        self.courses = {}

    def displayStudent(self):
        return 'Student Name: ' + self.name + '\n' + 'Student Number: ' + str(self.number)

    def addGrade(self, course, grade):
        self.courses[course] = grade

    def displayGPA(self):
    gpa = 0.0
    try:
        if self.courses.keys() != 0.0:
            for course in self.courses.keys():
                gpa = gpa + self.courses[course]
            return 'GPA of student ' + self.name + ' is ' + str(gpa / len(self.courses))

    except ZeroDivisionError:
        print('oops')


    def displayCourses(self):
        return [k for k in self.courses.keys() if self.courses[k] > 0]


if __name__ == '__main__':
    # Create first student object and add grades for each class
    student1 = Student('John', '013454900')
    student1.addGrade('uli101', 1.0)
    student1.addGrade('ops235', 2.0)
    student1.addGrade('ops435', 3.0)

    # Create second student object and add grades for each class
    student2 = Student('Jessica', '123456')
    student2.addGrade('ipc144', 4.0)
    student2.addGrade('cpp244', 3.5)
    student2.addGrade('cpp344', 0.0)

    # Display information for student1 object
    print(student1.displayStudent())
    print(student1.displayGPA())
    print(student1.displayCourses())

    # Display information for student2 object
    print(student2.displayStudent())
    print(student2.displayGPA())
    print(student2.displayCourses())

我想要做的是，如果在Student Name: John Student Number: 013454900 GPA of student John is 2.0 ['ops435', 'ops235', 'uli101'] Student Name: Jessica Student Number: 123456 GPA of student Jessica is 2.5 ['ipc144', 'cpp244'] 函数下没有添加任何课程，它应该显示ZeroDivisionError。

任何帮助将不胜感激。谢谢:)）

Answer 1

你可以抛出任何错误：

raise ErrorYouWantHere("Some Message")

在你的情况下

raise ZeroDivisionError("No course added")

但问题是，为什么你想要一个ZeroDivisionError。最好遵循错误的意图，当你尝试将某些东西除零时，ZeroDivisionError意味着抛出。

也许你想要一个ValueError？