Modul (%) in python not like in C?
J. Cliff Dyer
jcd at sdf.lonestar.org
Sun Sep 9 21:15:56 CEST 2007
Dotan Cohen wrote:
> FIrst of all, how is the % symbol (as in 70%6=4) called in English?
> Second, in Turbo C -111%10=-1 however in python -111%10=9. Is one or
> the other in error? Is this a known gotcha? I tried to google the
> subject however one cannot google the symbol %. Thanks in advance.
> Dotan Cohen
The % operator is called "modulo" in English. I don't think the
difference in implementation is an error. It's just a difference of
Python will always yield a number x = m%n such that 0 <= x < n, but
Turbo C will always yield a number such that if x = m%n -x = -m%n. That
is, since 111 % 10 = 1, -111 % 10 = -1. The two values will always
differ by n (as used above).
I'm sure there are mathematicians on the list who can give you a more
technical, precise explanation of the reasons for the different results.
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