用Python写一个学生成绩管理系统。

写一个学生成绩管理系统，可以先定义一个学生类，包含学生姓名、学号、课程名称和成绩等信息。然后，你可以创建多个学生对象，并对它们的信息进行存储、查询、更新等操作。下面是一个简单的例子：

class Student:
    def __init__(self, name, student_id, course, grade):
        self.name = name
        self.student_id = student_id
        self.course = course
        self.grade = grade

students = []

def add_student(name, student_id, course, grade):
    student = Student(name, student_id, course, grade)
    students.append(student)

def get_student_by_id(student_id):
    for student in students:
        if student.student_id == student_id:
            return student
    return None

def update_student_grade(student_id, new_grade):
    student = get_student_by_id(student_id)
    if student:
        student.grade = new_grade

add_student("Tom", "001", "Math", 85)
add_student("Jane", "002", "English", 90)

print(get_student_by_id("001").grade)  # Output: 85

update_student_grade("001", 95)

print(get_student_by_id("001").grade)  # Output: 95

这只是一个简单的例子，你可以根据你的需求进行更多的操作和扩展。