如何通过python更改CSV文件中的值? [英] How do you change a value in a CSV file through python?

问题描述

我需要能够找到和更改CSV股票文件中的值.我知道如何搜索值，但是当我尝试使用csv.writer时，它将返回错误.

I need to be able to find and change a value in a CSV stock file. I know how to search for a value but when I try to use the csv.writer then it returns an error.

Traceback (most recent call last):
  File "\\pbsrvfile\ExamAccounts$\ITCA76\ochot_krystian_a453\Task 3\Task 3.pyw", line 8, in <module>
    for row in writer:
TypeError: '_csv.writer' object is not iterable

我不知道为什么要这么做.到目前为止，我的代码是这样的:

I have no idea why it is doing that. So far I have this for the code:

import csv
code=input('Enter code to search: ')
stock=open ('Stock Levels.csv', 'wb')
writer=csv.writer(stock)
for row in writer:
    for field in row:
        if field==code:
            print('Record found! \n')
            print('Code: '+row[0])
            print('Product name: '+row[1])
            print('Target level: '+row[2])
            target = int(row[2])
            print('Current level: '+row[3]+'\n')
            current = int(row[3])
            restock_amount = target - current
            restocked_value = restock_amount + current
            writer.writerow[3](restocked_value)
            print(row[1]+' has been restocked to '+restocked_value)

任何人都可以告诉我如何解决错误或是否有另一种方法来修改值.我正在使用python 3.2.3

Can anyone tell me how to fix the error or if there is another way to modify the value. I am using python 3.2.3

推荐答案

尝试一下:

import csv
import os
code=input('Enter code to search: ')
with open ('Stock Levels.csv', 'r') as stock:
    reader=csv.reader(stock, delimiter=',')

    with open ('New Stock Levels.csv', 'w') as newStock:
        writer=csv.writer(newStock, delimiter=',')
        for row in reader:
            if code in row:
                print('Record found! \n')
                print('Code: '+row[0])
                print('Product name: '+row[1])
                print('Target level: '+row[2])
                target = int(row[2])
                print('Current level: '+row[3]+'\n')
                current = int(row[3])
                restock_amount = target - current
                restocked_value = restock_amount + current
                row[3] = restocked_value
                print(row[1]+' has been restocked to '+str(restocked_value))
            writer.writerow(row)
os.remove('Stock Levels.csv')
os.rename('New Stock Levels.csv', 'Stock Levels.csv')

如果使用with open而不是open，则不必关闭文件.

If you use with open instead of open you don't have to close the file.

代码的工作方式如下:

• 读取库存水平(您可能必须将定界符更改为任何 你有)
• 查看库存水平的每一行，如果看到，请对其进行修改 您要搜索的代码
• 将所有级别的库存水平写回到新库存 级别，包括修改后的行
• 删除旧文件以将New Stock Levels.csv文件重命名为旧版本(确保已备份)
• 将New Stock Levels.csv重命名为Stock Levels.csv

• Read stock levels (you might have to change the delimiter to whatever you have)
• Look at each line in stock levels and modify it if you see your code to search
• Write ALL lines of stock levels back to new stock levels, including the modified lines
• Delete the old file to enable the New Stock Levels.csv file to be renamed to the older version (make sure you have a backup)
• Rename New Stock Levels.csv to Stock Levels.csv

我认为您不能直接修改文件，我认为您始终必须先读取，修改，写入临时文件，然后重命名.

I don't think you can modify a file directly, I think you always have to read it, modify, write to temp file and then rename.

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