problem with byte string decoding

[oli]

hi,
i have a byte string and need to transform it to an ascii string due to legacy code reasons.
here is the code:

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MicroPython v1.8.4 on 2016-09-09; PYBv1.1 with STM32F405RG
Type "help()" for more information.
>>> x = b'\xf7\x03\x14\x04\x00\x01'
>>> x.decode('ascii')
'\x07\x03\x14\x04\x00\x01'

If you look at the first character in 'x' it is \xf7. After the decoding it is only x07. Is this a bug or do i understand the decode() wrong!?

Thanks for help!
best regards,
Oli

[oli]

Ok.... iPython gave me the answer:

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UnicodeDecodeError: 'ascii' codec can't decode byte 0xf7 in position 0: ordinal not in range(128)

Then the behaviour is clear. So now the question is, how to get rid of the 'b' before the string?
I need the transform because of the following code:

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x = b'\xf7\x03\x14\x04\x00\x01'
''.join(x)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: join expects a list of str/bytes objects consistent with self object

where as:

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x = '\xf7\x03\x14\x04\x00\x01'
''.join(x)
'\xf7\x03\x14\x04\x00\x01'

succeeds!?!?

Any ideas?

[Roberthh]

e.g.

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"".join([chr(c) for c in x])

[deshipu]

Why are you calling join() on a single string in the first place?

[oli]

@Roberthh: Thanks!
@deshipu: Like i said - legacy code not written by me, so i want to get it running, without changing to much - if it finally runs, then i will see, whether this stuff is necessary

[pythoncoder]

@oli Nevertheless @deshipu is correct. Issuing join() with a single string as its argument achieves precisely nothing. I'd question the quality of the original code.