Python object-oriented student management system

Posted by baudday on Fri, 07 Jan 2022 02:14:21 +0100

chart

target

Understand the analysis method of class internal function in the process of object-oriented programming development
Understand common functions, add, delete, modify and query

I. system requirements

Use the object-oriented programming idea to complete the development of student management system, as follows

System requirements: student data is stored in files
System functions: ① add, delete, modify and check student information, ② display all student information, save student information, ③ exit the system and other functions

Object oriented programming idea: analyzing roles, abstracting them into classes, defining classes, and creating objects

II. Preparation of procedure documents

2.1 analysis

Role analysis
- student
- management system

Precautions at work
1. In order to facilitate code maintenance, generally one role and one program file
2. The project shall have a main program entry, which is used to main py

2.2 creating program files

① Create a project directory, such as Student management system
② Create program file

Program entry file: main py
Student file: student registration py
Management system files: management system py

III. writing procedure

3.1 student registration py

Requirements:

Student information includes: Name Gender mobile number
Add__ str__ Magic function, easy to view student object information

3.1.2 program code

class Student registration():
    def __init__(self,full name,Gender,mobile phone):
        # Name Gender telephone
        self.full name=full name
        self.Gender=Gender
        self.mobile phone=mobile phone
    def __str__(self):
        # The destination output is not the memory address, but the specific content
        return f"{self.full name},{self.Gender},{self.mobile phone}"
# Create an object to temporarily verify the above code
# Xiao Ming = Student("Xiao Ming", "nv",17753355555)
# Print (Xiao Ming)
"""Xiao Ming,nv,17753355555"""

3.2 management system py

Requirements:

Where to store data: File student information data
- Load file data
- Save modified data to file
Form of data storage: list storage of student objects
system function
- Add, delete, modify and query
- Display all student information
- Save student information

3.2.1 definition class

class management system():
    def __init__(self):
        # List used to store data
        self.Student list t=[]

3.2.2 management system framework

The system functions are required to be recycled, and the user inputs different function serial numbers to perform different functions

step
- A defined program entry function
  - Load data
  - Display function menu
  - User input function serial number
  - Perform different functions according to the serial number entered by the user
- 2. Define system function functions, add / delete students, etc

Structure 1: entry function

class class_management system():
    def __init__(self):
        self.Student list=[]
    """ One entry function"""
    def run(self):
        # 1 load the file to obtain student data
        # 2 display function list
        # 3 user input selection function serial number
        # 4 realize different functions according to different serial numbers
    """Bifunctional function"""

> Above structure:  Below class , ① init Initialize student list, 
					  ② Entry function  run  And function functions  ,It's all the same   ,

Structure 2: function function

class class_management system():
    def __init__(self):
        self.Student list=[]
    """ One entry function"""
    def run(self):
		# 2 display function list
        self.Optional Features ()  #Class to call an instance method, use self
        
    """Bifunctional function"""
    # 2.1 display function menu
    @staticmethod
    def Optional Features ():  #There is no self in the bracket of static function
        print("Please select the following functions:")
        print("1: increase")

Structure 3 plus while – this works with main Py can run

#--*coding:utf-8*--
class class_management system():
    def __init__(self):
        self.Student list=[]
    """ One entry function"""
    def run(self):
        # 1 load the file to obtain student data
        pass
        while True:
            # 2 display function list
            self.Optional Features ()  #Class to call an instance method, use self
            # 3 user input selection function serial number
            Function serial number=int(input("Please select the function you want:"))
            # 4 realize different functions according to different serial numbers
            if Function serial number==1:
                self.increase()
            elif Function serial number==2:
                self.reduce()
            elif Function serial number==7:
                break
    """Bifunctional function"""
    # 2.1 display function menu static function
    @staticmethod
    def Optional Features ():  #There is no self in the bracket of static function
        print("Please select the following functions:")
        print("1: increase")
        print("2: Delete")
    # 2.2 add
    def increase(self):
        print("increase")
    # 2.3 minus
    def reduce(self):
        print("reduce")
    # 2.4 modification
    # 2.5 check
    # 2.6 display all
    # 2.7 preservation
    # 2.8 loading

# verification
if __full name__=="__main__":
    One middle school=class_management system()
    print(One middle school.Optional Features ())
    print(class_management system.Optional Features ())

3.3 main.py

demand

Guided package "management system",
Create the object and start the program

#--*coding:utf-8*--
# Guide Package
from  management system import *
# Create object startup management system
 Second middle school=class_management system()
Second middle school.run()

This big frame is ok, and the program can run normally

3.4 defining system function

3.4.1 add

The user is required to enter the name and gender to add the student to the system
step
- User input name... Input
- Create object = student registration class (name, gender, mobile phone)
- Add students to the list self Student list Append (student)
Initial 1 code

    # 2.2 add
    def increase(self):
        # 1. Please input the user's name, etc
        # 2 create student object
        # 3 add the object to the student list

code

#Adding student function requires creating Student object, so first import * student registration * module >
from Student registration import *
class management system():
       ..........
    # 2.2 add
    def increase(self):
        # 1. Please input the user's name, etc
        full name=input("Please enter your name:")
        Gender=input("Please enter your gender:")
        mobile phone=input("Please enter your mobile phone:")
        # 2. Create a student object. Student registration should be introduced here py
        student=Student registration(full name,Gender,mobile phone)
        print(student)
        # 3 add the object to the student list
        self.Student list.append(student)d
        print(self.Student list)

3.4.2 minus

The user is required to enter the name. If it is in the list, this student information will be deleted
step
- User input name
- Go through the student data list and check whether it exists. If yes, delete it. If not, print "no person found"
Initial 1 code

    # 2.3 minus	
    def reduce(self):
        # 1 user input student name
        # 2. If the history list is in, it will be deleted. If it is not in, it will prompt "no person found"

code

#Adding student function requires creating Student object, so first import * student registration * module >
from Student registration import *
class management system():
       ..........
    # 2.3 minus
    def reduce(self):
        # 1 user input student name
        Minus students=input("Please enter the name of the student you want to delete:")
        # 2. If the history list is in, it will be deleted. If it is not in, it will prompt "no person found"
        for i in self.Student list:
            if i.full name==Minus students:
                # Delete the student object
                self.Student list.remove(i)
                break
        # After going through the list,
        else:print("No one was found")
        print(self.Student list)

3.4.3 modification

The user is required to enter the name, update the object information if any, and create a new one if none
step

User input name \ gender \ mobile phone
Go through the student list, update it when it is, and "check no such person" when it is not

code

    # 2.4 modification
    def change(self):
        # 1 user input name \ gender \ mobile phone
        Change students=input("Please enter the student name to modify:")
        # 2. Go through the student list, update it when it is, and "check no such person" when it is not
        for i in self.Student list:
            if i.full name==Change students:
                i.full name=Change students
                i.Gender=input("Please enter student gender:")
                i.mobile phone=input("Please enter the student's mobile phone:")
                print(f"The student information has been modified successfully,full name:{Change students},Gender:{i.Gender},mobile phone:{i.mobile phone}")
                break
        else:print("No one was found")

3.4.4 check

The user is required to enter the name to find out whether there is
code

    # 2.5 check
    def check(self):
        Check students=input("Please enter the name of the student you want to find:")
        for i in self.Student list:
            if i.full name==Check students:
                print(f"The student information is as follows,full name:{Check students},Gender:{i.Gender},mobile phone:{i.mobile phone}")
                break
        else:print("No one was found")

3.4.5 view all

View all student information in the form of demand form
code

    # 2.6 display all
    def View all(self):
        print("full name\t Gender\t mobile phone")
        for i in self.Student list:
            print(f"{i.full name}\t{i.Gender}\t{i.mobile phone}")

3.4.6 save student information

It is required to save the modified student data to the file
step
- Open file
- Write data to file
- Close file

1 is the data written to the file the memory address of the student object? No! It should be understandable data
2 what data type should be in the file? String dictionary [{"Wang Wu": "Wang Wu", "male", "1775"}]

Extended dict

Function: collect the properties, methods and corresponding values of class objects or instance objects, and return a dictionary

class A():
    a=0   # Class properties
    def  __init__(self):
        self.b=1  #Instance object properties
aa=A()
# Returns all data in a class
print(A.__dict__)
# Return only instance object related
print(aa.__dict__)

"""
{'__module__': '__main__', 'a': 0, ....}  # Dictionary file
{'b': 1}  # Dictionary file
"""

-Initial code

    # 2.7 preservation
    def preservation(self):
        # 1 open file
        f=open("Student information.bata","w")
        # 2 write data to file  
        # 2.1 convert [Student object] to [list dictionary]  
        [i.__dict__ for i in Student object]
        # 2.2 the file is written to str() as a string
        f.write(str(New student list))        
        # 3 close file
        f.close()