How do I convert a Python 3 byte-string variable into a regular string?

问题

I have read in an XML email attachment with

bytes_string=part.get_payload(decode=False)

The payload comes in as a byte string, as my variable name suggests.

I am trying to use the recommended Python 3 approach to turn this string into a usable string that I can manipulate.

The example shows:

str(b'abc','utf-8')

How can I apply the b (bytes) keyword argument to my variable bytes_string and use the recommended approach?

The way I tried doesn't work:

str(bbytes_string, 'utf-8')

回答1:

You had it nearly right in the last line. You want

str(bytes_string, 'utf-8')

because the type of bytes_string is bytes, the same as the type of b'abc'.

回答2:

Call decode() on a bytes instance to get the text which it encodes.

str = bytes.decode()

回答3:

UPDATED:

TO NOT HAVE ANY b and quotes at first and end

As your code may have unrecognizable characters to 'utf-8' encoding, it's better to use just str without any additional parameters:

bad_bytes = b'\x02-\xdfI#)'
text = str( bad_bytes )[2:-1]

if you add 'utf-8' parameter, to these specific bytes, you should receive error.

As PYTHON 3 standard says, text would be in utf-8 now with no concern.

回答4:

How to filter (skip) non-UTF8 charachers from array?

To address this comment in @uname01's post and the OP, ignore the errors:

Code

>>> b'\x80abc'.decode("utf-8", errors="ignore")
'abc'

---

Details

From the docs, here are more examples using the same errors parameter:

>>> b'\x80abc'.decode("utf-8", "replace")
'\ufffdabc'
>>> b'\x80abc'.decode("utf-8", "backslashreplace")
'\\x80abc'
>>> b'\x80abc'.decode("utf-8", "strict")  
Traceback (most recent call last):
    ...
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x80 in position 0:
  invalid start byte

The errors argument specifies the response when the input string can’t be converted according to the encoding’s rules. Legal values for this argument are 'strict' (raise a UnicodeDecodeError exception), 'replace' (use U+FFFD, REPLACEMENT CHARACTER), or 'ignore' (just leave the character out of the Unicode result).

来源：https://stackoverflow.com/questions/31058055/how-do-i-convert-a-python-3-byte-string-variable-into-a-regular-string