[Python-Dev] PEP 461 - Adding % and {} formatting to bytes (original) (raw)

Ethan Furman ethan at stoneleaf.us
Wed Jan 15 22:32:01 CET 2014

On 01/15/2014 06:45 AM, Brett Cannon wrote: The PEP currently says::

format ------ The format mini language will be used as-is, with the behaviors as listed for %-interpolation. That's too vague; % interpolation does not support other format operators in the same way as str.format() does. % interpolation has specific code to support %d, etc. But str.format() gets supported for {:d} not from special code but because e.g. float.format('d') works. So you can't say "bytes.format() supports {:d} just like %d works with string interpolation" since the mechanisms are fundamentally different.

A question for anyone that has extensive experience in both %-formatting and .format-formatting: Would it be possible, at least for int and float, to take whatever is in the specifier and convert to %? Example:

"Weight: {wgt:-07f}".format(wgt=137.23)

would take the "-07f" and basically do a "%-07f" % 137.23 to get the ASCII to use?

-- Ethan

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