[Python-Dev] PEP 460: allowing %d and %f and mojibake (original) (raw)

Lennart Regebro regebro at gmail.com
Sun Jan 12 16:48:05 CET 2014

On Sat, Jan 11, 2014 at 8:40 PM, Kristján Valur Jónsson <kristjan at ccpgames.com> wrote:

Hi there. How about a compromise? Personally, I think adding the full complement of integer/float formatting to bytes is a bit over the top. How about just supporting two format specifiers? %b : interpolate a bytes object. If it doesn't have the buffer interface, error. %s : interpolate a str object, encoded to ASCII using 'strict' conversion.

This should cover the most common use cases. In particular, you could do this: Headers.append('Content-Length: %s'%(len(data),)) And then subsequently: Packet = b'%b%b'%(b"join(headers), data) For more complex formatting, you delegate to the more capable string class, but benefit from automatic ASCII conversion: Data = b"percentage = %s" % ("%4.2f" % (value,))

Although nice and clean as principle, I think it makes for somewhat messy code. I'm in favor of having float and integer specifiers as well.

I'm also for including %s, because it makes moving from Python 2 easier. But it should definitely error out if you try to feed it a non-ascii string.

//Lennart

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