python——学生管理系统

# ===============================学生管理系统================================
students = []
# 1、显示学生管理系统菜单
def show_menu():
    """显示学生管理系统菜单"""
    print("--------------------------------------")
    print("|1. 添加学生信息")
    print("|2. 查询学生信息")
    print("|3. 查询学生总数")
    print("|4. 删除学生信息")
    print("|5. 修改学生信息")
    print("|6. 退出系统")
    print("--------------------------------------")

def add_student():
    """添加"""
    name = input("输入学生姓名：")
    age = input("输入学生年龄：")
    grade = input("输入学生成绩：")
    student_id = int(input("输入学生ID："))
    if student_id is None:
        student_id = len(students) + 1001
    student = {
        "name":name,
        "age":age,
        "grade":grade,
        "id":student_id
    }
    students.append(student)
    print(f"成功添加学生:{name}(id:{student_id})")

def find_student(student_id):
    """查询"""
    for student in students:
        if student["id"] == student_id:
            print(student)
            return student
    return None

def count_student():
    """返回学生总数"""

    return len(students)

def get_select():
    choice = int(input("请输入您的选择："))
    return choice

def update_student():
    """修改学生信息"""
    student_id = int(input("输入要查询学生ID："))
    student = find_student(student_id)
    if student:
        print("请输入新信息(回车不修改姓名)")
        new_name = input(f"姓名[{student["name"]}]:") or student["name"]
        new_age = input(f"年龄[{student["age"]}]:")
        new_grade = input(f"成绩[{student["grade"]}]:")

        student["name"] = new_name
        if new_age:
            student["age"] = new_age
        if new_grade:
            student["grade"] = new_grade

        print(student)
    else:
        print("没有学生信息")

def delete_student():
    """删除学生信息"""
    student_id = int(input("输入要查询学生ID: "))
    for i, student in enumerate(students):
        if student["id"] == student_id:
            delete_name = student["name"]
            students.pop(i)
            print(f"已删除学生: {delete_name}")


while True:
    show_menu()
    num = get_select()
    if num == 1:
        # 添加学生信息
        add_student()
    elif num == 2:
        # 查询学生信息
        student_id = int(input("输入要查询学生ID："))
        find_student(student_id)
    elif num == 4:
        # 删除学生信息
        delete_student()
    elif num == 5:
        # 修改学生信息
        update_student()
    elif num == 6:
        # 退出系统
        print("谢谢使用本系统")
        break
    else:
        print("输入有误，重新输入1-6的数字")

file_1 = open("c:\Users\admin\Desktop\xian.txt")
file_2 = open("c:/Users/admin/Desktop/xian.txt")
file_3 = open(r"c:\Users\admin\Desktop\xian.txt")
# 相对路径
file_4 = open("./a.txt")
file_5 = open("D:/FXL/Python/25")