学生管理系统python作业代码

### Python 学生管理系统作业示例代码

#### 功能概述
此学生管理系统支持添加、删除、修改和查询学生信息等功能。通过文件操作持久化存储学生数据。

#### 主要功能模块
- 添加学生信息
- 删除学生信息
- 修改学生信息
- 查询学生信息
- 显示所有学生信息
- 统计学生总数

#### 完整代码实现

import os


def save_students(students, filename="students.txt"):
    """保存学生信息到文件"""
    with open(filename, 'w', encoding='utf-8') as wfile:
        for student in students:
            line = f"{student['id']},{student['name']},{student['age']}\n"
            wfile.write(line)


def load_students(filename="students.txt"):
    """从文件加载学生信息"""
    if not os.path.exists(filename):
        return []
    
    with open(filename, 'r', encoding='utf-8') as rfile:
        lines = rfile.readlines()
        
    students = [
        {
            "id": int(line.split(',')[0]),
            "name": line.split(',')[1],
            "age": int(line.split(',')[2])
        }
        for line in lines
    ]
    return students


def add_student():
    """添加新学生记录"""
    id_ = input("请输入学号:")
    name = input("请输入姓名:")
    age = input("请输入年龄:")

    new_student = {"id": int(id_), "name": name.strip(), "age": int(age)}
    all_students.append(new_student)
    save_students(all_students)
    print(f"成功添加 {new} 条学生信息")


def delete_student():
    """按ID删除指定学生记录"""
    del_id = int(input("请输入要删除学生的学号:"))
    global all_students
    
    before_len = len(all_students)
    all_students = [stu for stu in all_students if stu["id"] != del_id]
    after_len = len(all_students)
    
    if (before_len - after_len) > 0:
        save_students(all_students)
        print(f"已成功删除 ID={del_id} 的学生")
    else:
        print(f"未找到 ID={del_id} 的学生")


def modify_student():
    """更新现有学生的信息"""
    mod_id = int(input("请输入要修改的学生学号:"))

    target_stu = None
    for i, stu in enumerate(all_students):
        if stu["id"] == mod_id:
            target_stu = stu
            break
            
    if target_stu is None:
        print(f"找不到 ID={mod_id} 的学生")
        return
        
    update_name = input(f"当前名字是 [{target_stu['name']}], 新的名字是:")
    update_age = input(f"当前年龄是 [{target_stu['age']}], 新的年龄是:")

    updated_info = {}
    if update_name.strip() != '':
        updated_info['name'] = update_name.strip()
    if update_age.isdigit():
        updated_info['age'] = int(update_age)

    if bool(updated_info):
        index = next((index for (index, d) in enumerate(all_students) if d["id"] == mod_id), -1)
        if index >= 0:
            all_students[index].update(updated_info)
            save_students(all_students)
            print(f"成功更新了 ID={mod_id} 的学生信息")
        else:
            print("未能完成更新")
    else:
        print("没有任何更改被提交")


def query_student_by_id():
    """根据ID查找特定学生"""
    q_id = int(input("请输入要查询的学生学号:"))
    found = False
    
    for s in all_students:
        if s.get('id') == q_id:
            print(s)
            found = True
            break
                
    if not found:
        print(f"没有找到 ID={q_id} 的学生")


def show_all_students():
    """展示所有学生详情"""
    if len(all_students) == 0:
        print("目前无任何学生信息")
    else:
        for idx, item in enumerate(all_students, start=1):
            print(f"[{idx}] {item}")


def count_total_students():
    """统计并打印总人数"""
    num_of_students = len(all_students)
    print(f"系统中共有 {num_of_students} 名学生")


if __name__ == '__main__':
    menu_options = {
        1: ('添加学生', add_student),
        2: ('删除学生', delete_student),
        3: ('修改学生', modify_student),
        4: ('查询学生', query_student_by_id),
        5: ('显示所有学生', show_all_students),
        6: ('统计学生数量', count_total_students),
        7: ('退出程序', exit)
    }

    all_students = load_students()

    while True:
        try:
            print("\n=== 学生管理系统 ===\n")
            for key, value in menu_options.items():
                print(f'{key}. {value[0]}')
                
            choice = int(input('\n请选择您想要执行的操作编号：'))
            
            func_to_call = menu_options.get(choice)[1]

            if callable(func_to_call):
                func_to_call()
            elif isinstance(func_to_call, str) and func_to_call.lower().startswith('exit'):
                raise SystemExit
            else:
                print('无效选项，请重新输入')

        except ValueError:
            print('仅接受数字作为菜单选择，请重试.')
        except KeyboardInterrupt:
            print('\n\n强制终止请求收到，正在安全关闭...')
            break
        finally:
            pass