# Precidence of unary plus/minus relative to exponentiation

Warnes, Gregory R gregory_r_warnes at groton.pfizer.com
Thu Apr 3 17:56:35 CEST 2003

```Oops.  Again it appears that I was typing with my brain off....

-G

> -----Original Message-----
> From: Mikael Olofsson [mailto:mikael at isy.liu.se]
> Sent: Wednesday, April 02, 2003 2:45 AM
> To: python-list at python.org
> Subject: Re: Precidence of unary plus/minus relative to exponentiation
>
>
> On Tue, 1 Apr 2003 12:40:21 -0500
> "Warnes, Gregory R" <gregory_r_warnes at groton.pfizer.com> wrote:
> > The current operator precedence places unary plus and minus higher
> > than exponentiation.  This leads the counterintuitive result:
> >
> > 	>>> -2.0**2.0
> > 	-4.0
> >
> > Python's operator predicence is causing this to be interpreted as:
> >
> > 	>>> -(2.0**2.0)
> >
> > rather than the normal mathematical precidence, which would give
> >
> > 	>>> (-2.0)**2.0
> >
> > Is there a good reason for the Python order of precedence?
>
> I would say that the behaviour is what I expect. I would never expect
> -2.0**2.0 to mean (-2.0)**2.0. Nobody I've met in a
> mathematical context
> (engineers and mathematicians) have ever assumed your interpretation.
> Where have you seen that interpretation?
>
> /Mikael
>
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