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

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Article Directory

• 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

# 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)

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()