Python 3.1.1 string to hex
I am trying to use str.encode()
but I get
>>> "hello".encode(hex)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: must be string, not builtin_function_or_method
I have tried a bunch of variations and they seem to all work in Python 2.5.2, 开发者_开发知识库so what do I need to do to get them to work in Python 3.1?
The hex
codec has been chucked in 3.x. Use binascii
instead:
>>> binascii.hexlify(b'hello')
b'68656c6c6f'
In Python 3.5+, encode the string to bytes and use the hex()
method, returning a string.
s = "hello".encode("utf-8").hex()
s
# '68656c6c6f'
Optionally convert the string back to bytes:
b = bytes(s, "utf-8")
b
# b'68656c6c6f'
You've already got some good answers, but I thought you might be interested in a bit of the background too.
Firstly you're missing the quotes. It should be:
"hello".encode("hex")
Secondly this codec hasn't been ported to Python 3.1. See here. It seems that they haven't yet decided whether or not these codecs should be included in Python 3 or implemented in a different way.
If you look at the diff file attached to that bug you can see the proposed method of implementing it:
import binascii
output = binascii.b2a_hex(input)
binascii methodes are easier by the way
>>> import binascii
>>> x=b'test'
>>> x=binascii.hexlify(x)
>>> x
b'74657374'
>>> y=str(x,'ascii')
>>> y
'74657374'
>>> x=binascii.unhexlify(x)
>>> x
b'test'
>>> y=str(x,'ascii')
>>> y
'test'
Hope it helps. :)
The easiest way to do it in Python 3.5 and higher is:
>>> 'halo'.encode().hex()
'68616c6f'
If you manually enter a string into a Python Interpreter using the utf-8
characters, you can do it even faster by typing b
before the string:
>>> b'halo'.hex()
'68616c6f'
Equivalent in Python 2.x:
>>> 'halo'.encode('hex')
'68616c6f'
In Python 3, all strings are unicode. Usually, if you encode an unicode object to a string, you use .encode('TEXT_ENCODING')
, since hex
is not a text encoding, you should use codecs.encode()
to handle arbitrary codecs. For example:
>>>> "hello".encode('hex')
LookupError: 'hex' is not a text encoding; use codecs.encode() to handle arbitrary codecs
>>>> import codecs
>>>> codecs.encode(b"hello", 'hex')
b'68656c6c6f'
Again, since "hello" is unicode, you need to indicate it as a byte string before encoding to hexadecimal. This may be more inline with what your original approach of using the encode
method.
The differences between binascii.hexlify
and codecs.encode
are as follow:
binascii.hexlify
Hexadecimal representation of binary data.
The return value is a bytes object.
Type: builtin_function_or_method
codecs.encode
encode(obj, [encoding[,errors]]) -> object
Encodes obj using the codec registered for encoding. encoding defaults to the default encoding. errors may be given to set a different error handling scheme. Default is 'strict' meaning that encoding errors raise a ValueError. Other possible values are 'ignore', 'replace' and 'xmlcharrefreplace' as well as any other name registered with codecs.register_error that can handle ValueErrors.
Type: builtin_function_or_method
base64.b16encode
and base64.b16decode
convert bytes to and from hex and work across all Python versions. The codecs approach also works, but is less straightforward in Python 3.
Use hexlify - http://epydoc.sourceforge.net/stdlib/binascii-module.html
Yet another method:
s = 'hello'
h = ''.join([hex(ord(i)) for i in s]);
# outputs: '0x680x650x6c0x6c0x6f'
This basically splits the string into chars, does the conversion through hex(ord(char))
, and joins the chars back together. In case you want the result without the prefix 0x
then do:
h = ''.join([str(hex(ord(i)))[2:4] for i in s]);
# outputs: '68656c6c6f'
Tested with Python 3.5.3.
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