Read Me: following the implementation of the last simple shopping cart, it has been upgraded and optimized once again, and now it has the following functions:

1. There are customer operation and business operation, to realize that customers can buy things. When the amount is insufficient, press q to exit and print the shopping cart list

2. Businesses can add operations and modify commodity price operations

3. All the product information is stored in the product.txt file, for example, Watch: 1000, which exists in this form.

4. To run this program, you need to have the product information in the txt file, as shown above. Just follow the prompts

Mind mapping:

The code is as follows:

  1 #!/usr/bin/env python
  2 #-*- Coding:utf-8 -*-
  3 # Author:Eric.Shen
  4 #2018.02.06
  5 #path python3.5
  6 #Optimized shopping cart
  7 #User access:
  8 #1.Store the information of the goods in the file
  9 #2.Purchased goods, balance record
 10 #Merchant entrance:
 11 #1.Can add item 2.Modify commodity price
 12 #Store item list
 13 import fileinput
 14 product_list = []
 15 f = open("product.txt","r")#Open file
 16 for line in f.readlines():
 17     line =line.strip()#Remove the last line break
 18     index,item = line.split(":")#Get the front and back data by colon Division
 19     product_list.append((index,item))#Data added
 20 f.close()
 21 
 22 def print_product_list():
 23     for index,item in enumerate(product_list):
 24         print(index,item)
 25 #User entrance
 26 #User shopping
 27 def user_shopping():
 28     salary = input("Please enter your salary:")
 29     print_product_list()
 30     if salary.isdigit():
 31        salary = int(salary)
 32     shopping_list = []#Store user cart list
 33     while True:
 34         option = input("Buy whichever you like(Corresponding label): ")
 35         if option.isdigit():
 36             option = int(option)
 37             if option >= 0 and option <= len(product_list):
 38                 p_item = product_list[option]#Products selected by users
 39                 #print(product_list)
 40                 #print(p_item[1])
 41                 c_num = int(p_item[1])
 42                 if salary >= c_num:
 43                    shopping_list.append(p_item)
 44                    salary -= c_num
 45                    print("Successfully added shopping cart,Your balance still has%s"%(salary))
 46                 else:
 47                    print("You don't have enough money left%s element"%(salary))
 48             else:
 49                 print("Input error, please input again!")
 50         elif option == "q":
 51             print("----------------Shopping list---------------")
 52             for s_list in  shopping_list:
 53                 print(s_list)
 54             print("Your balance is%s"%(salary))
 55             print("..........exit.........")
 56             exit()
 57         else:
 58             print("Invalid input")
 59 
 60 #Merchant entrance
 61 #Merchants add products
 62 def add_product():
 63     name_of_product = input("Please enter the product name you want to add:")
 64     price_of_product = input("Please enter the price of the item you want to add:")
 65     f = open("product.txt","a")
 66     f.write(str("\n"+name_of_product)+": %s"%(price_of_product))
 67     f.close()
 68     print("Added successfully!\nexit----------")
 69 
 70 
 71 
 72 #Modify commodity price
 73 def change_price():
 74     print_product_list()#Print product list
 75     choice = input("Please enter your choice:")
 76     #name_of_change = input("Please enter the product name you want to change")
 77     price_of_change = input("Please enter the price you want to change:")
 78     if choice.isdigit():
 79         choice = int(choice)
 80         if choice >=0 and choice <= len(product_list):
 81             p_item = product_list[choice]#Selected products
 82             #c_num = int(p_item[1])#Convert to int type
 83             for line in fileinput.input("product.txt",inplace = "%s"%(choice)):#Modify the entered selection line
 84                 line = line.replace("%s"%(p_item[1]),"%s"%(price_of_change)).strip()
 85                 print(line)
 86             exit("Modification succeeded!")
 87         else:
 88             print("Invalid input")
 89     else:
 90         if choice == "q":
 91             exit("Sign out")
 92 
 93 
 94 
 95 
 96 
 97 
 98 
 99 
100 
101 
102 
103 
104 
105 if __name__ == "__main__":
106     print("--------------------------"
107           "--------------------------"
108           "\n"
109           "                  Welcome to the shopping menu      "
110           "\n"
111           "\n"
112           "Merchants please press b，Users please press c\n"
113           "--------------------------"
114           "--------------------------")
115     c_num = input("Please enter your choice:")#User selection
116     if c_num == "b":
117         print("--------------------------"
118               "--------------------------"
119               "\n"
120               "                  Welcome to the merchant interface      "
121               "\n"
122               "\n"
123               "To add a product, press a，Please press c\n"
124               "--------------------------"
125               "--------------------------")
126         c_num2 = input("Please enter your choice:")
127         if c_num2 == "a":
128             #Realize the function of adding goods
129            add_product()
130         if c_num2 == "c":
131             #Realize the function of commodity price modification
132            change_price()
133         else:
134             print("Wrong input!")
135     if c_num == "c":
136         print("--------------------------"
137               "--------------------------"
138               "\n"
139               "                  Welcome to the user interface      "
140               "\n"
141               "\n"
142               
143               "--------------------------"
144               "--------------------------")
145         #Shopping function
146         user_shopping()
147     else:
148         print("Input error program exit!")

End: if there is any mistake, please point it out. Welcome to disturb-_-