Python學生信息管理系統

#菜單
def meun():
    menu_info = '''＋－－－－－－－－－－－－－－－－－－－－－－＋
｜ １）添加學生信息                         ｜
｜ ２）顯示所有學生的信息                    ｜
｜ ３）刪除學生信息                         ｜
｜ ４）修改學生信息                         ｜
｜ ５）按學生成績高－低顯示學生信息           ｜
｜ ６）按學生成績低－高顯示學生信息           ｜
｜ ７）按學生年齡高－低顯示學生信息           ｜
｜ ８）按學生年齡低－高顯示學生信息           ｜
｜ ９）保存學生信息到文件（students.txt)     ｜
｜ １０）從文件中讀取數據（students.txt)     ｜
｜ 退出：其他任意按鍵＜回車＞                ｜
＋－－－－－－－－－－－－－－－－－-－－－－－＋
'''
    print(menu_info)
#｜１）添加學生信息
def add_student_info():
    l=[]
    while True:
        name=input('請輸入學生名字: ')
        if not name:
            print('~~~輸入完畢~~~')
            break
        try:
            age=int(input('學生年齡: '))
            score=int(input('學生成績: '))
        except:
            print('輸入錯誤,請重新輸入')
            continue
        lst={'name':name,'age':age,'score':score}
        l.append(lst)
    return l

# ｜２）顯示所有學生的信息
def show_student_info(student_info,del_name=''):
    if not student_info:
        pritn('無學生信息,返回菜單')
        return
        # center()返回一個原字符串居中, 並使用空格填充至長度width的新字符串。默認填充字符爲空格
    print('姓名'.center(8), '年齡'.center(4), '成績'.center(4))
    for i in student_info:
        print(i.get('name').center(10),str(i.get('age')).center(4),str(i.get('score')).center(8))

# ｜３）刪除學生信息
def del_student_info(student_info,del_name=''):
    if not del_name:
        del_name = input("請輸入刪除的學生姓名：")
    for info in student_info:
        if del_name == info.get("name"):
            return info
    raise IndexError("學生信息不匹配,沒有找到%s" %del_name)

# ｜４）修改學生信息
def mod_student_info(student_info):
    mod_name=input('請輸入要修改的學生名稱:')
    for info in student_info:
        if info.get('name')==mod_name:
            mod_age=int(input('請輸入學生年齡:'))
            mod_score=int(input('請輸入學生成績:'))
            info={'name':mod_name,'age':mod_age,'score':mod_score}
            return info
    raise IndexError('姓名不匹配:%s'%mod_name)

#用於年齡排序:
def get_age(*l):
    for x in l:
        return x.get('age')

#用於成績排序:
def get_score(*l):
    for x in l:
        return x.get('score')

from operator import itemgetter

# ｜５）按學生成績高－低顯示學生信息
def score_reduce(student_info):
    print('按學生成績高－低顯示')
    #reverse -- 排序規則，reverse = True 降序 ， reverse = False 升序（默認)
    mit=sorted(student_info,key=get_score,reverse=True)
    show_student_info(mit)

# ｜６）按學生成績低－高顯示學生信息
def score_rise(student_info):
    print("按學生成績低－高顯示")
    mit=sorted(student_info, key=get_score())

# ｜７）按學生年齡高－低顯示學生信息
def age_reduce(student_info):
    print("按學生年齡高－低顯示：")
    mit = sorted(student_info ,key = get_age,reverse = True)
    show_student_info(mit)

# ｜８）按學生年齡低－高顯示學生信息
def age_rise(student_info):
    print("按學生年齡低－高顯示：")
    mit = sorted(student_info ,key = get_age)
    show_student_info(mit)

# ｜９）保存學生信息到文件（students.txt)
def save_info(student_info):
    try:
        # 以寫模式打開，並清空文件內容
        student_txt = open('student.txt','w')
    except Exception as e:
        # 文件不存在，創建文件並打開
        student_txt = open('student.txt','x')
        for info in student_info:
            student_txt.write(str(info)+'\n')
        student_txt,close()

# ｜10）從文件中讀取數據（students.txt)
def read_info():
    old_info = []
    try:
        students_txt = open("students.txt")
    except:
        print("暫未保存數據信息")  # 打開失敗，文件不存在說明沒有數據保存
        return
    while True:
        info = students_txt.readline()
        if not info:
            break
        # print(info)
        info = info.rstrip()  # 去掉換行符
        # print(info)
        info = info[1:-1]  # 去掉｛｝
        # print(info)
        student_dict = {}  # 單個學生字典信息
        for x in info.split(","):  # 以，爲間隔拆分
            # print(x)
            key_value = []  # 開闢空間，key_value[0]存key,key_value[0]存value
            for k in x.split(":"):  # 以：爲間隔拆分
                k = k.strip()  # 去掉首尾空字符
                # print(k)
                if k[0] == k[-1] and len(k) > 2:  # 判斷是字符串還是整數
                    key_value.append(k[1:-1])  # 去掉　首尾的＇
                else:
                    key_value.append(int(k))
                # print(key_value)
            student_dict[key_value[0]] = key_value[1]  # 學生信息添加
        # print(student_dict)
        old_info.append(student_dict)  # 所有學生信息彙總
    students_txt.close()
    return old_info

def main():
    student_info=[]
    while True:
        meun()
        number=input('請輸入您的選項: ')
        if number == '1':
            student_info+=add_student_info()

        elif number == '2':
            show_student_info(student_info)

        elif number == '3':
            try:
                student_info.remove(del_student_info(student_info))
            except Exception as e:
                print(e)

        elif number == '4':
            try:
                student=mod_student_info(student_info)
            except Exception as e:
                print(e)
            else:
                # 首先按照根據輸入信息的名字，從列表中刪除該生信息，然後重新添加該學生最新信息
                student_info.remove(del_student_info(student_info, del_name=student.get("name")))
                student_info.append(student)

        elif number == '5':
            score_reduce(student_info)

        elif number == '6':
            score_rise(student_info)

        elif number == '7':
            age_reduce(student_info)

        elif number == '8':
            age_rise(student_info)

        elif number == '9':
            save_info(student_info)

        elif number == '10':
            student_info = read_info()

        else:
            break

        input('--回車返回菜單--')

main()