[python project] business card management system - difficulty: basic with complete executable code

Comprehensive application - business card management system

Dark horse programmer python basic project notes

Target

• variable
• process control
• function
• module

system requirement

• 1. Start the program, display the welcome interface of the business card management system, and display the function menu
• 2. The user selects different functions with numbers
• 3. According to the function selection, perform different functions
• 4. The user business card needs to record the user's name , phone number , QQ , email
• 5. If the specified business card is found, the user can choose to modify or delete the business card

step

1. frame building
2. Add business card
3. show all business cards
4. Query business card
5. After the query is successful, modify and delete the business card
6. Allow Python programs to run directly

01. Framework construction

Target

• Build the frame structure of business card management system
  1. Prepare the file , determine the file name, and ensure that the code can be written in the required position
  2. Write the main run loop to implement basic user input and judgment

1.1 Document preparation

1. New cards_main.pySave the main program function code
   • program entry
   • Every time the business card management system is started, mainit is started through this file
2. Create a functioncards_tools.py to save all business cards
   • Encapsulate functions such as adding , querying , modifying , and deleting business cards in different functions

1.2 Write the main run loop

• cards_mainAdd an infinite loop to

while True:

    # TODO(小明) 显示系统菜单

    action = input("请选择操作功能：")

    print("您选择的操作是：%s" % action)

    # 根据用户输入决定后续的操作
    if action in ["1", "2", "3"]:
        pass
    elif action == "0":
        print("欢迎再次使用【名片管理系统】")

        break
    else:
        print("输入错误，请重新输入")

String judgment

if action in ["1", "2", "3"]:

if action == "1" or action == "2" or action == "3":

1. Use to judge inagainst the listor , avoid using to concatenate complex logical conditions
2. User input is not used to intconvert, which can avoid the program running error once the user input is not a number

pass

• passIt is an empty statement that does nothing and is generally used as a placeholder statement
• is to maintain the integrity of the program structure

Infinite loop

• When developing software, if you do not want the program to exit immediately after execution
• An infinite loop can be added to the program
• It is up to the user to decide when to exit the program

TODO comments

• Followed #by TODO, used to mark the work that needs to be done

# TODO(作者/邮件) 显示系统菜单

1.3 cards_toolsAdd four new functions in

def show_menu():

    """显示菜单
    """
    pass

def new_card():

    """新建名片
    """
    print("-" * 50)
    print("功能：新建名片")


def show_all():

    """显示全部
    """
    print("-" * 50)
    print("功能：显示全部")


def search_card():

    """搜索名片
    """
    print("-" * 50)
    print("功能：搜索名片")

1.4 Importing modules

• cards_main.pyUse the importimport cards_toolsmodule in

import cards_tools

• Modify whilethe code for the loop as follows:

import cards_tools

while True:

    cards_tools.show_menu()

    action = input("请选择操作功能：")

    print("您选择的操作是：%s" % action)

    # 根据用户输入决定后续的操作
    if action in ["1", "2", "3"]:

        if action == "1":
            cards_tools.new_card()

        elif action == "2":
            cards_tools.show_all()

        elif action == "3":
            cards_tools.search_card()

    elif action == "0":
        print("欢迎再次使用【名片管理系统】")

        break
    else:
        print("输入错误，请重新输入：")

So far: cards_mainall the codes in all have been developed!

1.5 Completion show_menufunction

def show_menu():

    """显示菜单
    """
    print("*" * 50)
    print("欢迎使用【菜单管理系统】V1.0")
    print("")
    print("1. 新建名片")
    print("2. 显示全部")
    print("3. 查询名片")
    print("")
    print("0. 退出系统")
    print("*" * 50)

02. Store the structure of business card data

Programs are used to process data, and variables are used to store data

• Use a dictionary to record the details of each business card
• Use the list to uniformly record all business card dictionaries

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Define business card list variable

• cards_toolsAdd a list variable at the top of the file

# 所有名片记录的列表
card_list = []

Notice

1. All business card-related operations need to use this list, so it should be defined at the top of the program
2. When the program just runs, there is no data , so it is an empty list

03. Add business card

3.1 Function Analysis

1. Prompt the user to enter business card information in turn
2. Save business card information to a dictionary
3. Add dictionary to card list
4. Prompt that the business card is added

3.2 Implement the new_card method

• Follow the steps to implement the code

def new_card():

    """新建名片
    """
    print("-" * 50)
    print("功能：新建名片")

    # 1. 提示用户输入名片信息
    name = input("请输入姓名：")
    phone = input("请输入电话：")
    qq = input("请输入 QQ 号码：")
    email = input("请输入邮箱：")

    # 2. 将用户信息保存到一个字典
    card_dict = {
    
    "name": name,
                 "phone": phone,
                 "qq": qq,
                 "email": email}

    # 3. 将用户字典添加到名片列表
    card_list.append(card_dict)

    print(card_list)
    
    # 4. 提示添加成功信息
    print("成功添加 %s 的名片" % card_dict["name"])

Tip: In PyCharm, you can use to SHIFT + F6modify the variable name uniformly

04. Show all business cards

4.1 Function Analysis

• Loop through the business card list and display the information of each dictionary in sequence

4.2 Basic code implementation

def show_all():

    """显示全部
    """
    print("-" * 50)
    print("功能：显示全部")

    for card_dict in card_list:

        print(card_dict)
        

• The display effect is not good!

4.3 Add title and use \tdisplay

def show_all():
    """显示全部
    """
    print("-" * 50)
    print("功能：显示全部")

    # 打印表头
    for name in ["姓名", "电话", "QQ", "邮箱"]:
        print(name, end="\t\t")

    print("")

    # 打印分隔线
    print("=" * 50)

    for card_dict in card_list:

        print("%s\t\t%s\t\t%s\t\t%s" % (card_dict["name"],
                                        card_dict["phone"],
                                        card_dict["qq"],
                                        card_dict["email"]))

4.4 Increase the judgment that there is no business card record

def show_all():
    """显示全部
    """
    print("-" * 50)
    print("功能：显示全部")

    # 1. 判断是否有名片记录
    if len(card_list) == 0:
        print("提示：没有任何名片记录")

        return

Notice

• Use in a function returnto indicate return
• If returnthere is no content after , it just means that the function will not execute subsequent codes until this point

05. Query business card

5.1 Function Analysis

1. Prompt the user for a name to search for
2. Iterate through the list based on the name entered by the user
3. After searching for the specified business card, perform subsequent operations

5.2 Code implementation

• Realization of query function

def search_card():

    """搜索名片
    """
    print("-" * 50)
    print("功能：搜索名片")

    # 1. 提示要搜索的姓名
    find_name = input("请输入要搜索的姓名：")

    # 2. 遍历字典
    for card_dict in card_list:

        if card_dict["name"] == find_name:

            print("姓名\t\t\t电话\t\t\tQQ\t\t\t邮箱")
            print("-" * 40)
            
            print("%s\t\t\t%s\t\t\t%s\t\t\t%s" % (
                card_dict["name"],
                card_dict["phone"],
                card_dict["qq"],
                card_dict["email"]))

            print("-" * 40)
            
            # TODO(小明) 针对找到的字典进行后续操作：修改/删除

            break
    else:
        print("没有找到 %s" % find_name)

• Add business card operation function: modify / delete / return to main menu

def deal_card(find_dict):

    """操作搜索到的名片字典

    :param find_dict:找到的名片字典
    """
    print(find_dict)

    action_str = input("请选择要执行的操作 "
                       "[1] 修改 [2] 删除 [0] 返回上级菜单")

    if action == "1":
        print("修改")
    elif action == "2":
        print("删除")

06. Modification and deletion

6.1 Delete business card after successful query

• Since the dictionary records found are already saved in the list
• To delete a business card record, just delete the corresponding dictionary in the list

    elif action == "2":
        card_list.remove(find_dict)

        print("删除成功")

6.2 Modify name card

• Since the dictionary records found are already saved in the list
• To modify the business card record, you only need to modify the data of each key-value pair in the corresponding dictionary in the list

    if action == "1":

        find_dict["name"] = input("请输入姓名：")
        find_dict["phone"] = input("请输入电话：")
        find_dict["qq"] = input("请输入QQ：")
        find_dict["email"] = input("请输入邮件：")

        print("%s 的名片修改成功" % find_dict["name"])

Modify business card refinement

• If the user does not want to modify some business card content when using it , what should be done? —— Since the function provided by the system inputcannot meet the requirements, then define a new function to expand the function input_card_infoof the systeminput

def input_card_info(dict_value, tip_message):

    """输入名片信息

    :param dict_value: 字典原有值
    :param tip_message: 输入提示信息
    :return: 如果输入，返回输入内容，否则返回字典原有值
    """
    # 1. 提示用户输入内容
    result_str = input(tip_message)

    # 2. 针对用户的输入进行判断，如果用户输入了内容，直接返回结果
    if len(result_str) > 0:

        return result_str
    # 3. 如果用户没有输入内容，返回 `字典中原有的值`
    else:

        return dict_value

Shebang07. The symbol ( #!) on LINUX

• #!This symbol is called ShebangorSha-bang
• ShebangUsually used at the beginning of the first lineUnix of a system script
• Specify the interpreter to execute this script file

Steps to use Shebang

• 1. Use whichto query python3the path where the interpreter is located

$ which python3

• 2. Modify the main python file to be run , add the following to the first line

#! /usr/bin/python3

• 3. Modify the file permissions of the main python file and increase the execution permissions

$ chmod +x cards_main.py

• 4. Execute the program when needed

./cards_main.py

Complete code reproduction

1. card_main.py

#  #！ python解释器
import card_tools

while True:
	#  显示功能菜单
	card_tools.show_menu()
	
	action_str = input("请选择希望执行的操作： ")
	print("您选择的操作是【%s】" % action_str)
	
	if action_str in ["1", "2", "3"]:
		if action_str == "1":
			card_tools.new_card()
		if action_str == "2":
			card_tools.show_all()
		if action_str == "3":
			card_tools.search_card()
		pass
	elif action_str == "0":
		print("欢迎再次使用【名片管理系统】")
		break
		# pass
	else:
		print("您输入的不正确，请重新选择")

2. card_tools.py

card_list = []


def show_menu():
	"""显示菜单"""
	print("*"*50)
	print("欢迎使用【名片管理系统V1.0】")
	print(" ")
	print("1.新增名片")
	print("2.显示全部")
	print("3.搜索名片")
	print(" ")
	print("0.退出系统")
	print("*" * 50)
	
	
def new_card():
	"""新增名片"""
	print("-" * 50)
	print("新增名片")
	
	name_str = input("请输入姓名：")
	phone_str = input("请输入电话：")
	qq_str = input("请输入QQ：")
	email_str = input("请输入邮箱：")
	card_dict = {
    
    
		"name": name_str,
		"phone": phone_str,
		"qq": qq_str,
		"email": email_str
	}
	card_list.append(card_dict)
	print("添加 %s 的名片成功！" % name_str)
	
	
def show_all():
	"""显示所有名片"""
	print("-" * 50)
	print("显示所有名片")
	if len(card_list) == 0:
		print("当前没有任何名片记录，请使用新增功能添加名片！")
		return
	for name in ["姓名", "电话", "QQ", "邮箱"]:
		print(name, end = "\t\t")
	print(" ")
	print("="*50)
	for card_dict in card_list:
		print("%s\t\t%s\t\t%s\t\t%s" % (card_dict["name"], card_dict["phone"], card_dict["qq"], card_dict["email"]))
	
	
def search_card():
	"""搜索名片"""
	print("-" * 50)
	print("搜索名片")
	find_name = input("请输入要查找的姓名：")
	
	for card_dict in card_list:
		if card_dict["name"] == find_name:
			print("找到了")
			for name in ["姓名", "电话", "QQ", "邮箱"]:
				print(name, end = "\t\t")
			print(" ")
			print("=" * 50)
			print("%s\t\t%s\t\t%s\t\t%s" % (card_dict["name"], card_dict["phone"], card_dict["qq"], card_dict["email"]))
			deal_card(card_dict)
			break
		else:
			print("抱歉，没有找到 %s 的信息！" % find_name)
			
			
def deal_card(find_dict):
	# print(find_dict)
	action_str = input("请选择要执行的操作【1】 修改  【2】 删除  【0】 返回上一级目录")
	if action_str == "1":
		find_dict["name"] = input_card_info(find_dict["name"], "姓名：")
		find_dict["phone"] = input_card_info(find_dict["phone"], "电话：")
		find_dict["qq"] = input_card_info(find_dict["qq"], "QQ：")
		find_dict["email"] = input_card_info(find_dict["email"], "邮箱：")
		print("修改名片成功！")
	elif action_str == "2":
		card_list.remove(find_dict)
		print("删除名片成功")
		

def input_card_info(dict_value, tip_message):
	result_str = input(tip_message)
	if len(result_str) > 0:
		return result_str
	else:
		return dict_value