根据输入在python中编辑CSV文件

Question

I am to create a program that collects data from a csv file, in which is stored item names and stock. I would like to display to the user how much of, for example apple, is in stock.

Item #      Item name    Item stock    Item price
12345670    Apple        20            0.70

What would you like to buy?: 12345670
How much would you like to buy?: 10

And what I'm trying to do is edit the CSV file to display the new figure of 10 since there are 20 apples and the user purchases 10. I have tried various methods but they all give me strange errors. My expected output would be:

Item #      Item name    Item stock
12345670    Apple        20

What would you like to buy?: 12345670
How much would you like to buy?: 10
You have bought 10 apple(s) for a price of £7
There are 10 apples left in stock

If the user purchases too many apples:

Item #      Item name    Item stock
12345670    Apple        20

What would you like to buy?: 12345670
How much would you like to buy?: 30
There are not enough apple(s) in stock to buy that amount
Would you like to buy all there is?: yes
You have bought 20 apple(s) for the price of £14

This is my code

import csv
restart = 10
list1 = []
price = 0
print("Type 'end' to end")
while restart == 10:
        file1 = open("CSV File TASK 2.csv", "rt")
        file2 = csv.reader(file1)
        print(" ")
        order = input("Type the item number of your chosen number: ")
        if order == 'end':
                break
        for row in file2:
                for field in row:
                        if order in field:
                                amount = int(input("How much of that item?: "))
                                row3 = int(row[3])
                                if amount > row3:
                                        print("There is not enough of that item in stock")
                                        print("Please try again")
                                        continue
                                row2 = float(row[2])
                                row1 = str(row[1])
                                price = amount * row2 + price
                                newstock = row3 - amount
                                print("You have bought {} {}(s) for the price of £{:.2f}".format(amount, row1, price))
                                print("Your subtotal is currently at {:.2f}".format(price))
                                receipt = ("{} {} {} {} {}".format(row[0]+" ", row[1], str(amount), "{:10.2f}".format(float(row[2])), "{:10.2f}".format(amount * float(row[2]))))
                                list1.append(receipt)
print('\n'.join('{}: {}'.format(*k) for k in enumerate(list1)))

Python 3.5.2. Please and thanks in advance.

Answer 1

You could use this:

import csv

f     = open('test.csv', 'r') # Here your csv file
r     = csv.reader(f) 
lines = [l for l in r]

ItemX = 0



Item   = input("What would you like to buy? ")
Amount = input("How much would you like to buy? ")

for x in range(len(lines)):
    if lines[x][0] == Item:
        ItemX = x
    else:
        continue1 = True # Does nothing

f.close()

fw    = open('test.csv', 'w') # Here your csv file

lines[ItemX][2] = float(lines[ItemX][2]) - float(Amount)

writer = csv.writer(fw)
writer.writerows(lines)

fw.close()