HEX decoding in Python 3.2

Question

In Python 2.x, I can do this:

>>> '4f6c6567'.decode('hex_codec') 'Oleg' 

But in Python 3.2, I ran into this error:

 >>> b'4f6c6567'.decode('hex_codec') Traceback (most recent call last): File "<pyshell#25>", line 1, in <module> b'4f6c6567'.decode('hex_codec') TypeError: decoder did not return a str object (type=bytes) 

According to docs, hex_codec should contain "byte to byte mappings." Thus, the byte string object is correctly used here.

How can I get rid of this error to avoid cumbersome workarounds for converting from hex encoded text?

Answer 1

In Python 3, the bytes.decode() method is used to decode raw bytes in Unicode, so you should get the decoder from the codecs module using codecs.getdecoder() or codecs.decode() for bytes -to- bytes encodings:

 >>> codecs.decode(b"4f6c6567", "hex_codec") b'Oleg' >>> codecs.getdecoder("hex_codec")(b"4f6c6567") (b'Oleg', 8) 

The latter function seems to be missing from the documentation, but has a useful docstring.

You can also look at binascii.unhexlify() .