On Mon, May 01, 2017 at 11:38:20PM +1000, Nick Coghlan wrote:
We're definitely open to offering better formatting options for bytes.hex().
My proposal in https://bugs.python.org/issue22385 was to define a new formatting mini-language (akin to the way strftime works, but with a much simpler formatting mini-language): http://bugs.python.org/issue22385#msg292663
However, a much simpler alternative would be to 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 disagree with this approach. There's nothing special about bytes.hex() here, perhaps we want to format the output of hex() or bin() or oct(), or for that matter "%x" and any of the other string templates? In fact, this is a string operation that could apply to any character string, including decimal digits. Rather than duplicate the API and logic everywhere, I suggest we add a new string method. My suggestion is str.chunk(size, delimiter=' ') and str.rchunk() with the same arguments: "1234ABCDEF".chunk(4) => returns "1234 ABCD EF" rchunk will be useful for money or other situations where we group from the right rather than from the left: "$" + str(10**6).rchunk(3, ',') => returns "$1,000,000" And if we want to add bells and whistles, we could accept a tuple for the size argument: # Format mobile phone number in the Australian style "04123456".rchunk((4, 3)) => returns "0412 345 678" # Format an integer in the Indian style str(123456789).rchunk((3, 2), ",") => returns "12,34,56,789" In the OP's use-case: bytes("abcde", "ascii").hex().chunk(2) => returns '61 62 63 64 65' bytes("abcde", "ascii").hex().chunk(4) => returns '6162 6364 65' I don't see any advantage to adding this to bytes.hex(), hex(), oct(), bin(), and I really don't think it is helpful to be grouping the characters by the number of bits. Its a string formatting operation, not a bit operation. -- Steve