python: bug or feature?

[Olaf Delgado]

In article <8msimd$bia$1 at nnrp1.deja.com>,
	Keith Murphy <kpmurphy at my-deja.com> writes:
> the first one works, but the second one always returns a 0.
> 
> ( (e%4 == 0) & (self.current == e-1) )
> 
> ( e%4 == 0 & self.current == e-1 )

So, what did you want it to return?

The '&' stands for a bitwise 'and' operation, which binds stronger
than the test for equality. So the second expression is equivalent to

  ( e%4 == (0 & self.current) == e-1 )

which, as '0 & anything' is always 0, is equivalent to

  ( e%4 == 0 == e-1 )

which, in turn, is equivalent to

  ( e%4 == 0 and 0 == e-1 )

which can only be true if 1 is divisible by 4 (which it isn't, at
least not in ordinary arithmetic).

What you presumably wanted is

  ( e%4 == 0 and self.current == e-1 )

-- 
  ////
  Olaf  Delgado Friedrichs, Bielefeld, Germany
  `='   --- http://www.mathematik.uni-bielefeld.de/~delgado ---