用python写一个学生信管理系统

好的，以下是一个简单的学生信息管理系统的Python代码：

# 定义一个学生类
class Student:
    def __init__(self, name, id, grade):
        self.name = name
        self.id = id
        self.grade = grade

# 定义一个学生信息管理系统类
class StudentManagementSystem:
    def __init__(self):
        self.students = []

    # 添加学生信息
    def add_student(self, name, id, grade):
        student = Student(name, id, grade)
        self.students.append(student)

    # 删除学生信息
    def remove_student(self, id):
        for student in self.students:
            if student.id == id:
                self.students.remove(student)
                return True
        return False

    # 修改学生信息
    def modify_student(self, id, name=None, grade=None):
        for student in self.students:
            if student.id == id:
                if name:
                    student.name = name
                if grade:
                    student.grade = grade
                return True
        return False

    # 查询学生信息
    def query_student(self, id):
        for student in self.students:
            if student.id == id:
                return student
        return None

    # 显示所有学生信息
    def display_students(self):
        for student in self.students:
            print("Name: {}, ID: {}, Grade: {}".format(student.name, student.id, student.grade))

# 测试代码
if __name__ == '__main__':
    sms = StudentManagementSystem()

    # 添加学生信息
    sms.add_student("Jack", 1001, 90)
    sms.add_student("Lucy", 1002, 80)
    sms.add_student("Tom", 1003, 70)

    # 显示学生信息
    sms.display_students()

    # 修改学生信息
    sms.modify_student(1002, name="Lucy Smith", grade=85)
    print("\nAfter modify:")
    sms.display_students()

    # 查询学生信息
    student = sms.query_student(1003)
    if student:
        print("\nQuery result:")
        print("Name: {}, ID: {}, Grade: {}".format(student.name, student.id, student.grade))

    # 删除学生信息
    sms.remove_student(1001)
    print("\nAfter remove:")
    sms.display_students()

这个学生信息管理系统可以添加、删除、修改、查询和显示所有学生的信息。你可以根据需要进行修改和扩展。