math.nroot [was Re: A brief question.]

George Sakkis gsakkis at rutgers.edu
Sun Jul 3 17:11:02 CEST 2005


"Tom Anderson" <twic at urchin.earth.li> wrote:

> >> And finally, does Guido know something about arithmetic that i don't, or
> >> is this expression:
> >>
> >> -1.0 ** 0.5
> >>
> >> Evaluated wrongly?
> >
> > No, it is evaluated according to the rules of precedence. It is
> > equivalent to -(1.0**0.5). You are confusing it with (-1.0)**0.5 which
> > fails as expected.
>
> Ah. My mistake. I submit that this is also a bug in python's grammar.
> There's probably some terribly good reason for it, though.

How about 'conformance with standard mathematic notation', does this
count for a terribly good reason ? What would one expect to be the
result of 5^2 - 2^2, 29 or 21 ? Would you expect 5^2 + - 2^2 to be
different, even if you write it as 5^2 + -2  ^ 2  ? White space is not
significant in math AFAIK ;-)

George




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