Python:无法写入 CSV 文件

我有这段 Python 代码:

import csv 
 
def analyse(csvFileToRead, csvFileToWrite): 
    # open file to read 
    openedCsvFileToRead = open(csvFileToRead) 
    reader = csv.reader(openedCsvFileToRead) 
 
    # open file to write 
    openedCsvFileToWrite = open(csvFileToWrite) 
    writer = csv.writer(openedCsvFileToWrite) 
 
    for row in reader: 
        date = row[8] 
        if date[0] == "5": 
            writer.writerow(row) 
 
    # close file 
    openedCsvFileToRead.close() 
    openedCsvFileToWrite.close() 
 
if __name__ == "__main__": 
    analyse("mydata.csv", "mynewdata.csv") 

当使用 Python 3.4 运行时，我收到以下错误消息:

Traceback (most recent call last): 
  File "main.py", line 40, in <module> 
    analyse("mydata.csv", "mynewdata.csv") 
  File "main.py", line 25, in analyse 
    writer.writerow(row) 
io.UnsupportedOperation: not writable 

我做错了什么？ 我使用的是 Windows 7 64 位。

请您参考如下方法:

您必须以写入模式打开文件:

openedCSvFileToWrite = open(csvFileToWrite, "w") 

请注意，在 Python 2.x 中，docs始终使用 'wb'，而不是 'w'。