Precidence of unary plus/minus relative to exponentiation
Mikael Olofsson
mikael at isy.liu.se
Wed Apr 2 02:45:15 EST 2003
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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