Introducing the Python object-oriented version of the student management system

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• Python object-oriented version student management system
• Objective
• 1. System requirements
• 2. Prepare program files
• • 2.1 Analysis
  • 2.2 Create program files
• 3. Write program
• • 3.1 student.py
  • ##3.1.2 Program code
  3.2 managerSystem.py
  • 3.2.1 Define class
    • 3.2.2 Management system framework
  3.3 main.py
  • 3.4 Define system Function function
  • 3.4.1 Add function
    • 3.4.2 Delete student
    • 3.4.3 Modify student information
    • 3.4. 5 Query student information
    • 3.4.6 Display all student information
    • 3.4.7 Save student information
    • 3.4.8 Load student information
4. Summary

Objective

Understand the analysis method of internal functions of classes in the object-oriented development process
• Understand common system functions
• Add
  • Delete
  • Modify
  • Query

1. System requirements

System requirements: Student data is stored in files中
• System functions: add students, delete students, modify student information, query student information, display all student information, save student information and exit the system, etc.

2. Prepare program files

2.1 Analysis

Character analysis
• Student
  • Management System

Notes on work

In order to facilitate the maintenance of the code, there is usually one role per role Program file;
1. The project must have a main program entry, which is usually
2. main.py

Create the project directory, for example:

The program file is as follows:

• Student file: student.py
• Management system file: managerSystem.py

Requirements:

• Add
__str__
• magic method, convenient View student object information

class Student(object):
    def __init__(self, name, gender, tel):
        self.name = name
        self.gender = gender
        self.tel = tel    def __str__(self):
        return f'{self.name}, {self.gender}, {self.tel}'

Requirements:

• Load file data
  • Modify the data and save it to the file
  Form of data storage: list storage student object
• System function
• Add student
  • Delete student
  • Modify student
  • Query Student information
  • Display all student information
  • Save student information
  • Exit the system
##3.2.1 Definition class

class StudentManager(object):
    def __init__(self):
        # 存储数据所用的列表
        self.student_list = []

Requirements: System functions are used cyclically, and users enter different function numbers to perform different functions.

Steps

Define program entry function
• Load data
  • Display function menu
    • User input function number
    Perform different functions according to the function number entered by the user
    • Define system function functions, add, delete students, etc.

  class StudentManager(object):
      def __init__(self):
          # 存储数据所用的列表
          self.student_list = []
  
      # 一. 程序入口函数，启动程序后执行的函数
      def run(self):
          # 1. 加载学员信息
          self.load_student()
  
          while True:
              # 2. 显示功能菜单
              self.show_menu()
  
              # 3. 用户输入功能序号
              menu_num = int(input('请输入您需要的功能序号：'))
  
              # 4 根据用户输入的功能序号执行不同的功能
              if menu_num == 1:
                  # 添加学员
                  self.add_student()
              elif menu_num == 2:
                  # 删除学员
                  self.del_student()
              elif menu_num == 3:
                  # 修改学员信息
                  self.modify_student()
              elif menu_num == 4:
                  # 查询学员信息
                  self.search_student()
              elif menu_num == 5:
                  # 显示所有学员信息
                  self.show_student()
              elif menu_num == 6:
                  # 保存学员信息
                  self.save_student()
              elif menu_num == 7:
                  # 退出系统
                  break
  
      # 二. 定义功能函数
      # 2.1 显示功能菜单
      @staticmethod
      def show_menu():
          print('请选择如下功能-----------------')
          print('1:添加学员')
          print('2:删除学员')
          print('3:修改学员信息')
          print('4:查询学员信息')
          print('5:显示所有学员信息')
          print('6:保存学员信息')
          print('7:退出系统')
  
      # 2.2 添加学员
      def add_student(self):
          pass
  
      # 2.3 删除学员
      def del_student(self):
          pass
  
      # 2.4 修改学员信息
      def modify_student(self):
          pass
  
      # 2.5 查询学员信息
      def search_student(self):
          pass
  
      # 2.6 显示所有学员信息
      def show_student(self):
          pass
  
      # 2.7 保存学员信息
      def save_student(self):
          pass
  
      # 2.8 加载学员信息
      def load_student(self):
          pass

  Copy after login

# 1. 导入managerSystem模块from managerSystem import *# 2. 启动学员管理系统if __name__ == '__main__':
    student_manager = StudentManager()

    student_manager.run()

3.4.1 Add function

• Steps

• User input name, gender, mobile phone number

  Create the student object
  • Create the student object Add to list
  Code

• # 添加学员函数内部需要创建学员对象，故先导入student模块from student import *class StudentManager(object):
  		......
      
      # 2.2 添加学员
      def add_student(self):
          # 1. 用户输入姓名、性别、手机号
          name = input('请输入您的姓名：')
          gender = input('请输入您的性别：')
          tel = input('请输入您的手机号：')
  
          # 2. 创建学员对象：先导入学员模块，再创建对象
          student = Student(name, gender, tel)
  
          # 3. 将该学员对象添加到列表
          self.student_list.append(student)
          
          # 打印信息
          print(self.student_list)
          print(student)

  Copy after login
3.4.2 Delete student

Requirement: The user enters the name of the target student, and if the student exists, delete the student.

Steps
• The user enters the name of the target student
• Traverse the student data list. If the student name entered by the user exists, delete it. Otherwise, it will prompt that the student does not exist.
  • Code

    # 2.3 删除学员：删除指定姓名的学员
    def del_student(self):
        # 1. 用户输入目标学员姓名
        del_name = input('请输入要删除的学员姓名：')
        
        # 2. 如果用户输入的目标学员存在则删除，否则提示学员不存在
        for i in self.student_list:
            if i.name == del_name:
                self.student_list.remove(i)
                break
        else:
            print('查无此人！')

        # 打印学员列表，验证删除功能
        print(self.student_list)

    # 2.4 修改学员信息
    def modify_student(self):
        # 1. 用户输入目标学员姓名
        modify_name = input('请输入要修改的学员的姓名：')
        # 2. 如果用户输入的目标学员存在则修改姓名、性别、手机号等数据，否则提示学员不存在
        for i in self.student_list:
            if i.name == modify_name:
                i.name = input('请输入学员姓名：')
                i.gender = input('请输入学员性别：')
                i.tel = input('请输入学员手机号：')
                print(f'修改该学员信息成功，姓名{i.name},性别{i.gender}, 手机号{i.tel}')
                break
        else:
            print('查无此人！')

    # 2.5 查询学员信息
    def search_student(self):
        # 1. 用户输入目标学员姓名
        search_name = input('请输入要查询的学员的姓名：')

        # 2. 如果用户输入的目标学员存在，则打印学员信息，否则提示学员不存在
        for i in self.student_list:
            if i.name == search_name:
                print(f'姓名{i.name},性别{i.gender}, 手机号{i.tel}')
                break
        else:
            print('查无此人!')

    # 2.6 显示所有学员信息
    def show_student(self):
        print('姓名\t性别\t手机号')
        for i in self.student_list:
            print(f'{i.name}\t{i.gender}\t{i.tel}')

class A(object):
    a = 0

    def __init__(self):
        self.b = 1aa = A()# 返回类内部所有属性和方法对应的字典print(A.__dict__)# 返回实例属性和值组成的字典print(aa.__dict__)

    # 2.7 保存学员信息
    def save_student(self):
        # 1. 打开文件
        f = open('student.data', 'w')

        # 2. 文件写入学员数据
        # 注意1：文件写入的数据不能是学员对象的内存地址，需要把学员数据转换成列表字典数据再做存储
        new_list = [i.__dict__ for i in self.student_list]
        # [{'name': 'aa', 'gender': 'nv', 'tel': '111'}]
        print(new_list)

        # 注意2：文件内数据要求为字符串类型，故需要先转换数据类型为字符串才能文件写入数据
        f.write(str(new_list))

        # 3. 关闭文件
        f.close()

    # 2.8 加载学员信息
    def load_student(self):
        # 尝试以"r"模式打开数据文件，文件不存在则提示用户；文件存在（没有异常）则读取数据
        try:
            f = open('student.data', 'r')
        except:
            f = open('student.data', 'w')
        else:
            # 1. 读取数据
            data = f.read()

            # 2. 文件中读取的数据都是字符串且字符串内部为字典数据，故需要转换数据类型再转换字典为对象后存储到学员列表
            new_list = eval(data)
            self.student_list = [Student(i['name'], i['gender'], i['tel']) for i in new_list]
        finally:
            # 3. 关闭文件
            f.close()