What's the correct way to convert bytes to a h

Question

What's the correct way to convert bytes to a hex string in Python 3?

I see claims of a bytes.hex method, bytes.decode codecs, and have tried other possible functions of least astonishment without avail. I just want my bytes as hex!

Answer 1

Since Python 3.5 this is finally no longer awkward:

>>> b'\xde\xad\xbe\xef'.hex()
'deadbeef'

and reverse:

>>> bytes.fromhex('deadbeef')
b'\xde\xad\xbe\xef'

works also with the mutable bytearray type.

Answer 2

If you want to convert b'\x61' to 97 or '0x61', you can try this:

[python3.5]
>>>from struct import *
>>>temp=unpack('B',b'\x61')[0] ## convert bytes to unsigned int
97
>>>hex(temp) ##convert int to string which is hexadecimal expression
'0x61'

Reference:https://docs.python.org/3.5/library/struct.html

Answer 3

Python has bytes-to-bytes standard codecs that perform convenient transformations like quoted-printable (fits into 7bits ascii), base64 (fits into alphanumerics), hex escaping, gzip and bz2 compression. In Python 2, you could do:

b'foo'.encode('hex')

In Python 3, str.encode / bytes.decode are strictly for bytes<->str conversions. Instead, you can do this, which works across Python 2 and Python 3 (s/encode/decode/g for the inverse):

import codecs
codecs.getencoder('hex')(b'foo')[0]

Starting with Python 3.4, there is a less awkward option:

codecs.encode(b'foo', 'hex')

These misc codecs are also accessible inside their own modules (base64, zlib, bz2, uu, quopri, binascii); the API is less consistent, but for compression codecs it offers more control.

Answer 4

it can been used the format specifier %x02 that format and output a hex value. For example:

>>> foo = b"tC\xfc}\x05i\x8d\x86\x05\xa5\xb4\xd3]Vd\x9cZ\x92~'6"
>>> res = ""
>>> for b in foo:
...     res += "%02x" % b
... 
>>> print(res)
7443fc7d05698d8605a5b4d35d56649c5a927e2736

Answer 5

import codecs
codecs.getencoder('hex_codec')(b'foo')[0]

works in Python 3.3 (so "hex_codec" instead of "hex").

Answer 6

OK, the following answer is slightly beyond-scope if you only care about Python 3, but this question is the first Google hit even if you don't specify the Python version, so here's a way that works on both Python 2 and Python 3.

I'm also interpreting the question to be about converting bytes to the str type: that is, bytes-y on Python 2, and Unicode-y on Python 3.

Given that, the best approach I know is:

import six

bytes_to_hex_str = lambda b: ' '.join('%02x' % i for i in six.iterbytes(b))

The following assertion will be true for either Python 2 or Python 3, assuming you haven't activated the unicode_literals future in Python 2:

assert bytes_to_hex_str(b'jkl') == '6a 6b 6c'

(Or you can use ''.join() to omit the space between the bytes, etc.)