基于python制作简易版学生信息管理系统-巨人网络通讯

一、前言
二、需求分析
三、主函数
四、功能菜单
五、录入信息
六、保存信息
七、查找信息
八、删除信息
九、修改信息
十、显示信息
十一、按成绩排序
十二、统计人数
十三、最后记得运行主函数
十四、将程序打包成可执行exe文件

一、前言

本篇博客对于文件操作、字典、列表、匿名函数以及sort()等内置函数进行了系统的整理操作，以设计一个学生信息管理系统的形式展示，具体概念方法等会在代码后进行分析讲述，请读者仔细分析每一处解析，对于基础巩固将会有很大的帮助，其中还有每一块代码的设计思路图，逻辑分析会有一定的提升。

二、需求分析

本程序需要用到os模板首先导入，并命名要存储信息的文件

import os
File_Object_Name = 'Student_Inforation.txt'

三、主函数

def Main():
    while True:
        Menu()
        _Select = int(input('Please select operation:'))
        if _Select in [0, 1, 2, 3, 4, 5, 6, 7]:
            if _Select == 0:
                _Answer = input('Do you want to log out?(Y/N)')
                if _Answer == 'Y' or _Answer == 'y':
                    print('Thank for you use!!!')
                    break
                    pass
                else:
                    continue
                    pass
                pass
            elif _Select == 1:
                Insert_Infor()
                pass
            elif _Select == 2:
                Search_Infor()
                pass
            elif _Select == 3:
                Delete_Infor()
                pass
            elif _Select == 4:
                Change_Infor()
                pass
            elif _Select == 5:
                Sort()
                pass
            elif _Select == 6:
                Count_Total_Num()
                pass
            elif _Select == 7:
                Show_Infor()
                pass
            pass
        else:
            print('Error Input!!!')
            pass

四、功能菜单

def Menu():
    print('=========Student Information Management System=========')
    print('---------------------Function menu---------------------')
    print('             1、Input Student Information')
    print('             2、Search Student Information')
    print('             3、Delete Student Information')
    print('             4、Change Student Information')
    print('             5、Sort According to Score')
    print('             6、Count Total Student Number')
    print('             7、Show All Student Information')
    print('             0、Log Out')
    print('-------------------------------------------------------')
    pass

五、录入信息

def Insert_Infor():
    Student_Infor_List = []  # 创建一个学生信息空列表，后面会用到
    while True:
        Stu_Id = input('Please input the id(such as 1001,1002):')
        if not Stu_Id:  # 空的字符串转为bool类型为False，非空为True，此处若是输入为空会直接跳出循环。（空列表、字典、元组等都满足）
            break
            pass
        Stu_Name = input('Please input the name:')
        if not Stu_Name:
            break
            pass
        try:
            English_Score = int(input('Please input the English score:'))
            Python_Score = int(input('Please input the Python score:'))
            Java_Score = int(input('Please input the Java score:'))
            pass
        except:
            print('Error Input(not int),please input again')
            continue
            pass
        # 将每个学生的信息放入一个字典当中
        Student_Infor_Dict = {'Id': Stu_Id, 'Name': Stu_Name, 'English': English_Score, 'Python': Python_Score, 'Java': Java_Score}
        # 将一个字典作为一个元素放入学生信息列表
        Student_Infor_List.append(Student_Infor_Dict)  # 使用 append() 方法来添加列表项
        _Answer = input('Whether to input more?(Y/N)')
        if _Answer == 'Y' or _Answer == 'y':
            continue
            pass
        else:
            break
            pass
        pass
    # 将学生信息列表中的字典元素保存到文件之中，调用Keep_Infor()函数
    Keep_Infor(Student_Infor_List)
    print('Input Finished')
    pass

六、保存信息

def Keep_Infor(List):
    File_Object = open(File_Object_Name, mode='a', encoding='utf-8')
    # 打开一个文件用于追加。如果该文件已存在，文件指针将会放在文件的结尾。也就是说，新的内容将会被写入到已有内容之后。如果该文件不存在，创建新文件进行写入。
    for item in List:
        File_Object.write(str(item)+'\n')
        pass
    # 将传入的列表中的字典元素强制转换成字符串类型并拼接上换行符写入文件
    File_Object.close()

七、查找信息

def Search_Infor():
    Student_Query = [] # 空列表，之后用于存放查找到的学生信息
    while True:
        Student_Id = ''
        Student_Name = ''
        if os.path.exists(File_Object_Name):
        # os.path模块主要用于文件的属性获取，os.path.exists()就是判断括号里的文件是否存在，括号内的可以是文件路径/名。
            Search_Mode = int(input('search by id(1) or by name(2):'))
            if Search_Mode == 1:
                Student_Id = input('Please input id:')
                pass
            elif Search_Mode == 2:
                Student_Name = input('Please input name:')
                pass
            else:
                print('Error Input,try again!')
                Search_Infor()
                pass
            with open(File_Object_Name, 'r', encoding='utf-8')as File_Object:  # 只读模式打开文件并将类对象赋给File_Object
                Student_List = File_Object.readlines()  # readlines()按行读取，一次性读取所有内容，返回一个列表，每一行内容作为一个元素
                for item in Student_List:  # 遍历列表中元素
                    _Dict = eval(item)
                    # 由于是以字符串类型保存到文件中，此时item相当于'dict'形式，要将其用eval()函数转换为字典,即脱掉''。
                    if Student_Id:  # 如果选的是按照姓名查找，则此空字符串已经不再为空，bool类型为True
                        if Student_Id == _Dict['Id']:
                            Student_Query.append(_Dict)
                            pass
                        pass
                    elif Student_Name:
                        if Student_Name == _Dict['Name']:
                            Student_Query.append(_Dict)
                            pass
                        pass
                    pass
                if Student_Query == []:  # 仍为空说明未找到。
                    print('no such student,try again')
                    Search_Infor()  # 再次调用函数
                    pass
                pass
            pass
        else:
            print('Still no such file to keep student information!')
            pass
        print(Student_Query[0])  # 此时该列表中只有一个字典元素，直接打印输出
        Student_Query.clear()  # 调用内置函数清空列表，方便下次使用
        _Answer = input('Whether to search others?(Y/N)')
        if _Answer == 'Y' or _Answer == 'y':
            continue
            pass
        else:
            return
        pass
    pass

八、删除信息

def Delete_Infor():
    while True:
        Student_Id = input('Please input the student‘s id that you want to delete:')
        if Student_Id:
            if os.path.exists(File_Object_Name):
                with open(File_Object_Name, 'r', encoding='utf-8')as File1:
                    Old_Student_Infor = File1.readlines()  # 读取每行作为元素放入Old_Student_Infor列表
                    pass
                pass
            else:
                Old_Student_Infor = []
                pass
            Flag = False  # 是否删除成功的标志
            if Old_Student_Infor:
                with open(File_Object_Name, 'w', encoding='utf-8')as File2:
                    _Dict = {}
                    for item in Old_Student_Infor:
                        _Dict = eval(item)  # 将删除信息之前的列表元素转化为字典形式赋给_Dict
                        if _Dict['Id'] != Student_Id:
                            File2.write(str(_Dict)+'\n')
                            # 如果与要删除的信息的Id不同，覆盖写入原文件
                            pass
                        else:
                            Flag = True  # 如果相同的话，则不写入文件中，相当于删除成功
                            pass
                        pass
                    if Flag:
                        print('Student information of {} has been delete'.format(Student_Id))
                        pass
                    else:
                        print('Can not find student of id:{}'.format(Student_Id))
                        pass
                    pass
                pass
            else:
                print('file have no student information')
                break
                pass
            Show_Infor()
            _Answer = input('Whether to delete more?(Y/N)')
            pass
        if _Answer == 'Y' or _Answer == 'y':
            continue
            pass
        else:
            break
            pass
        pass
    pass

九、修改信息

def Change_Infor():
    Show_Infor()
    if os.path.exists(File_Object_Name):
        with open(File_Object_Name, 'r', encoding='utf-8')as old_file:
            Old_Student_Infor = old_file.readlines()
            pass
        pass
    else:
        return
    Student_Id = input('Please input the id you wanna change:')
    if Student_Id:
        with open(File_Object_Name, 'w', encoding='utf-8')as new_file:
            for item in Old_Student_Infor:
                _dict = dict(eval(item))
                if _dict['Id'] == Student_Id:
                    print('Find it,can change it!')
                    while True:
                        try:
                            _dict['Name'] = input('Please input new name:')
                            _dict['English'] = input('Please input new English score:')
                            _dict['Python'] = input('Please input new Python score:')
                            _dict['Java'] = input('Please input new Java score:')
                            pass
                        except:
                            print('Error Input!!!Try again')
                            pass
                        new_file.write(str(_dict)+'\n')
                        print('Successfully change!')
                        break
                        pass
                    pass
                else:
                    print('Can‘t find it')
                    new_file.write(str(_dict)+'\n')
                    pass
                pass
            pass
        pass
    _Answer = input('Whether to change more?(Y/N)')
    if _Answer == 'y' or _Answer == 'Y':
        Change_Infor()
        pass
    else:
        return
    pass

十、显示信息

def Show_Infor():
    Infor_List = []
    if os.path.exists(File_Object_Name):
        with open(File_Object_Name, 'r', encoding='utf-8')as File_Object:
            Stu_List = File_Object.readlines()
            for item1 in Stu_List:
                Infor_List.append(dict(eval(item1)))
                pass
            if Infor_List:
                for item2 in Infor_List:
                    print(item2)
                    pass
                pass
            else:
                print('no student')
                pass
            pass
        pass
    else:
        print('no such file')
        pass
    pass

十一、按成绩排序

def Sort():
    Show_Infor()
    Infor_List = []
    if os.path.exists(File_Object_Name):
        with open(File_Object_Name, 'r', encoding='utf-8')as File_Object:
            Student_List = File_Object.readlines()
            for item in Student_List:
                _Dict = dict(eval(item))
                Infor_List.append(_Dict)
                pass
            pass
        pass
    else:
        print('no such file')
        return
    Sort_Mode = bool(input('Please input sort mode(0、ascending order|1、descending order)'))
    if not Sort_Mode:  # ascending order
        reverse_mode = True
        pass
    else:  # descending order
        reverse_mode = False
        pass
    Specific_Sort_Mode = int(input('Sort by English(1),by Python(2),by Jave(3),by total(4):'))
    if Specific_Sort_Mode == 1:
        Infor_List.sort(key=lambda x: int(x['English']), reverse=reverse_mode)
        pass
    elif Specific_Sort_Mode == 2:
        Infor_List.sort(key=lambda x: int(x['Python']), reverse=reverse_mode)
        pass
    elif Specific_Sort_Mode == 3:
        Infor_List.sort(key=lambda x: int(x['Java']), reverse=reverse_mode)
        pass
    elif Specific_Sort_Mode == 4:
        Infor_List.sort(key=lambda x: int(x['English']) + int(x['Python']) + int(x['Java']), reverse=reverse_mode)
        pass
    else:
        print('Error Input,try again')
        Sort()
        pass
    for item in Infor_List:
        print(item)
        pass
    pass

sort()函数原型: list.sort(key=None, reverse=False)

key参数：
key接受的是一个只有一个形参的函数，形式如下
def f(a):
return len(a)
key接受的函数返回值，表示此元素的权值，sort将按照权值大小进行排序
reverse参数：
reverse接受的是一个bool类型的值 (Ture or False),表示是否颠倒排列顺序,一般默认的是False

十二、统计人数

def Count_Total_Num():
    if os.path.exists(File_Object_Name):
        with open(File_Object_Name, 'r', encoding='utf-8')as File_Object:
            Stu_List = File_Object.readlines()
            _Count = len(Stu_List)
            if _Count >= 2:
                print('A total of {} students')
                pass
            elif _Count ==1:
                print('A single student!')
                pass
            else:
                print('no student!')
                pass
            pass
        pass
    else:
        print('still no such file!')
        pass
    pass