Question or problem about Python programming:
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!
How to solve the problem:
Since Python 3.5 this is finally no longer awkward:
>>> b'\xde\xad\xbe\xef'.hex() 'deadbeef'
>>> bytes.fromhex('deadbeef') b'\xde\xad\xbe\xef'
works also with the mutable
>>> import binascii >>> binascii.hexlify('foo'.encode('utf8')) b'666f6f' >>> binascii.unhexlify(_).decode('utf8') 'foo'
See this answer:
Python 3.1.1 string to hex
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:
In Python 3,
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')
Starting with Python 3.4, there is a less awkward option:
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.
import codecs codecs.getencoder('hex_codec')(b'foo')
works in Python 3.3 (so “hex_codec” instead of “hex”).
binascii.hexlify() will convert
bytes to a
bytes representing the ascii hex string. That means that each byte in the input will get converted to two ascii characters. If you want a true
str out then you can
.decode("ascii") the result.
I included an snippet that illustrates it.
import binascii with open("addressbook.bin", "rb") as f: # or any binary file like '/bin/ls' in_bytes = f.read() print(in_bytes) # b'\n\x16\n\x04' hex_bytes = binascii.hexlify(in_bytes) print(hex_bytes) # b'0a160a04' which is twice as long as in_bytes hex_str = hex_bytes.decode("ascii") print(hex_str) # 0a160a04
from the hex string
"0a160a04" to can come back to the
binascii.unhexlify("0a160a04") which gives back