[Python-ideas] Add an option for delimiters in bytes.hex()

Nick Coghlan ncoghlan at gmail.com
Tue May 2 00:52:40 EDT 2017


On 2 May 2017 at 03:34, Ethan Furman <ethan at stoneleaf.us> wrote:
> On 05/01/2017 07:04 AM, Juancarlo Añez wrote:
>>
>> On Mon, May 1, 2017 at 9:38 AM, Nick Coghlan wrote:
>>
>>> just support two
>>> keyword arguments to hex(): "delimiter" (as you suggest) and
>>> "chunk_size" (defaulting to 1, so you get per-byte chunking by
>>> default)
>>
>>
>> I'd expect "chunk_size"  to mean the number of hex digits (not bytes) per
>> chunk.
>
> I was also surprised by that.  Also, should Python be used on a machine
> with, say, 24-bit words then a chunk size of three makes more sense that one
> of 1.5.  ;)

I came up with a possible alternative scheme on the issue tracker:

    def hex(self, *, group_digits=None, delimiter=" "):
        """B.hex() -> string of hex digits
        B.hex(group_digits=N) -> hex digits in groups separated by *delimeter*

        Create a string of hexadecimal numbers from a bytes object::

        >>> b'\xb9\x01\xef'.hex()
        'b901ef'
        >>> b'\xb9\x01\xef'.hex(group_digits=2)
        'b9 01 ef'
        """

Advantages of this approach:

- grouping by digits generalises more obviously to other bases (e.g.
if similar arguments were ever added to the hex/oct/bin builtins)
- by using "group_digits=None" to indicate "no grouping", the default
delimiter can be a space rather than the empty string

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia


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