如何写回在python中打开csv文件 [英] how to write back to open csv file in python

问题描述

我正在尝试浏览一个csv文件，验证邮政编码并将城市和州写到csv文件的最后一列.

I'm trying to go through a csv file, validate zip codes and write the city and state to the last column in the csv file.

我设法获取了csv数据并获取了城市和州，但是我不知道如何将新数据写入最后一列.像 this 这样的示例显示了如何创建csv ，但不适用于现有的csv.

I managed to get the csv data and get the city and state, but I don't understand how to write the new data to the last column. SO examples like this show how to create a csv, but not work with an existing csv.

到目前为止，这是我的代码:

here is my code so far:

with open("propertyOutput.csv", "rbw") as fp:
    reader = csv.DictReader(fp, skipinitialspace=True)
    table = [row for row in reader]
    for rows in table:
        stringNeed = rows['zip']
        if not stringNeed.isdigit(): 
            print"not number"  #would like to write this to the column
            pass
        else:
            if not len(stringNeed) == 5:  
                print"string not 5 long"  # would like to write this to the column
            else:
                x = getCityState(stringNeed)
                print x  # would like to write this to the column

推荐答案

您需要分两个步骤进行操作:

You need to do it in two steps:

1. 读取csv文件并存储信息

1. Read the csv file and store information

import csv

with open("propertyOutput.csv", "rbw") as fp:
    reader = csv.DictReader(fp, skipinitialspace=True)
    table = [row for row in reader]
    header = reader.fieldnames 

将信息写入新文件或替换旧文件

Write the information to an new file or replace old file

with open("propertyOutput.csv", "wb") as fp:
    writer = csv.DictWriter(fp, header)
    for row in table:
        if not stringNeed.isdigit(): 
            rows['zip'] = "not number"
        # even more stuff to check and edit here
        # write the edited row
        writer.writerow(row)

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