Modul (%) in python not like in C?

[mensanator at aol.com]

On Sep 10, 1:38 am, Dennis Lee Bieber <wlfr... at ix.netcom.com> wrote:
> On Sun, 09 Sep 2007 22:57:24 -0700, "mensana... at aol.com"
> <mensana... at aol.com> declaimed the following in comp.lang.python:
>
>
>
> > But, in general, doesn't (-11,-4) also satisfy
> >   x = y *   a +   b
> > -70 = 6 * -11 + (-4)?
>
> > Do you overpay your car loans and wait for a refund?
>
>         As I stated, integer division and modulo are linked... Which is
> "correct" is probably dependent upon the language specifications.

I didn't make an opinion on which was "correct".

> Either
> method allows one to recover the original value from the output of
> divmod.

My point was the need to satisfy x = y * a + b doesn't
explain WHY divmod(-70,6) returns (-12,2) instead of (-11,-4).

>
>         Whether that works in the way you intend is a different matter -- my
> car loans usually have interest factors which are applied per payment by
> payment date, so using modulo (or divmod) is not applicable, one must
> actually build the table of payments one at a time (especially since the
> automatic payments taken from paychecks gets "corrupted" during
> holidays, when paychecks are issued a day or two earlier than normal,
> meaning less interest charges during that period and more applied to
> principle; with more on interest the following week, and less on
> interest).

Ok, poor example. Suppose instead we are slicing a 70 character string
from the right. We certainly CAN'T have 6 12-letter slices, can we?
But we can have 6 11-letter slices with 4 characters left over.

And there are probably examples where (-12,2) would make more sense,
although I can't think of one at the moment.

Again, I'm not saying (-12,2) is wrong, just that the explanation
why it's (-12,2) is wanting since there are cases where (-11,-4)
makes more sense.

> --
>         Wulfraed        Dennis Lee Bieber               KD6MOG
>         wlfr... at ix.netcom.com             wulfr... at bestiaria.com
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