On Fri, Jul 12, 2002 at 10:47:34AM -0400, Guido van Rossum wrote:
Guido, can you please, for our enlightenment, tell us what are the reasons you feel %(foo)s was a mistake?
Because of the trailing 's'. It's very easy to leave it out by mistake, and because the definition of printf formats skips over spaces (don't ask me why), the first character of the following word is used as the type indicator.
In case that wasn't clear, I agree with that - I asked because I wanted this in writing for the record.
BTW: IIRC, it skips over spaces because spaces are a valid format modifier (meaning "pad with spaces").