TypeError: a bytes-like object is required, not 'str' when trying to write in csv file

Question

我必须将 Python 2 中编写的以下代码转换为 Python3:

with open('C:/path_to_csv_file/fold1_1.csv', 'wb') as csvfile:
    spamwriter = csv.writer(csvfile, delimiter=',', quotechar='|', quoting=csv.QUOTE_MINIMAL)
    for row, timeseq in izip(fold1, fold1_t):
        spamwriter.writerow([unicode(s).encode("utf-8") +'#{}'.format(t) for s, t in izip(row, timeseq)])

我的Python3代码如下：

with open('C:/Users/path_to_csv_file/fold1_1.csv', 'wb') as csvfile:
    spamwriter = csv.writer(csvfile, delimiter=',', quotechar='|', quoting=csv.QUOTE_MINIMAL)
    for row, timeseq in zip(fold1, fold1_t): 
        for s, t in zip(row, timeseq):
            bytes_var = s.encode('utf-8') +'#{}'.format(t).encode('utf-8') 
            spamwriter.writerow(bytes_var)

fold1 包含：

fold1 = ['¢©§','¢©§','¢©§']

fold1_t 包含：

fold1_t =[[0, 15, 173999],[0, 457325, 306],[0, 62954, 432]]

当我尝试执行上面的代码时，出现以下错误：

TypeError: a bytes-like object is required, not 'str'

变量 bytes_var 是字节类型，所以通常它应该可以工作。我是不是在从 Python2 到 Python3 的转换中做错了什么来得到那个错误？谢谢。

Answer 1

您需要将 wb 更改为 w。此外，在 python 3 中，您可以通过直接将表达式传递到字符串的花括号中来格式化字符串，因此

s.encode('utf-8') +'#{}'.format(t).encode('utf-8')

可以

f'{s}#{t}'.encode('utf-8')

一共：

import csv

fold1 = ['¢©§','¢©§','¢©§']
fold1_t =[[0, 15, 173999], [0, 457325, 306], [0, 62954, 432]]

with open('C:/path_to_csv_file/fold1_1.csv', 'w') as csvfile:
    spamwriter = csv.writer(csvfile, delimiter=',', quotechar='|', quoting=csv.QUOTE_MINIMAL)
    for row, timeseq in zip(fold1, fold1_t): 
        for s, t in zip(row, timeseq):
            bytes_var = s.encode('utf-8') + f'#{t}'.encode('utf-8') 
            spamwriter.writerow(bytes_var)

Answer 2

csv 模块是 Python2 -> Python3 转换不是很简单的模块之一。基础文件应以文本形式打开，不再以二进制文件形式打开，但行尾为空。

所以我会写：

with open('C:/path_to_csv_file/fold1_1.csv', 'w', newline='', encoding='utf-8') as csvfile:
    spamwriter = csv.writer(csvfile, delimiter=',', quotechar='|', quoting=csv.QUOTE_MINIMAL)
    for row, timeseq in izip(fold1, fold1_t):
        spamwriter.writerow([s +'#{}'.format(t) for s, t in izip(row, timeseq)])

当前错误是由于csv模块发送的是unicode字符串，而底层文件需要字节。

TypeError: a bytes-like object is required, not 'str' when trying to write in csv file

TypeError: a bytes-like object is required, not 'str' when trying to write in csv file

python

csv

python-2.x

python-3.x