Python3 | Expected type 'union[bytes, bytearray], got 'str' instead

Question

I have a stable working project with python. It's running on python 2.7. I upgraded it to python 3.x. So, it's not working on Python3.

The logic is writing values to csv file.

Broken code is that:

csv = io.BytesIO()

csv.write('fiscalYear\t'
                      'VKN\t'
                      'recordPeriod\t'
                      'enteredBy\t'
                      'entredDate\t'
                      'entryNumber\t'
                      'entryComment\t'
                      'batchID\t'
                      'batchDescription\t'
                      'totalDebit\t'
                      'totalCredit\t'
                      'amountOriginalExchangeRate\t'
                      'amountOriginalExchangeRateSource\t'
                      'amountOriginalExchangeRateComment\n'
            )

return csv.getvalue()

My problem is that:

Expected type 'union[bytes, bytearray], got 'str' instead

Python log error:

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

I need your help!

https://docs.python.org/3/howto/pyporting.html#text-versus-binary-data — deceze, Oct 02 '18 at 13:11

score 2 · Answer 1 · answered Oct 02 '18 at 13:10

2

As the error message says, you should pass binary data, not strings. Instead of

csv.write(my_text)

write

csv.write(my_text.encode())

to convert it to binary.

answered Oct 02 '18 at 13:10

blue_note

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score 2 · Accepted Answer · answered Oct 02 '18 at 13:12

You are writing a string (Unicode) to a BytesIO object. You should probably switch your BytesIO to a StringIO. If you truly want bytes, you can convert your Unicode strings to bytes using their encode() method, passing your preferred encoding scheme (e.g. 'utf-8').

Python3 | Expected type 'union[bytes, bytearray], got 'str' instead

2 Answers2