[Tutor] toggle idiom?

[dman]

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On Wed, May 08, 2002 at 03:36:15PM -0700, Sean 'Shaleh' Perry wrote:

| > I would argue that
| >     a =3D not a
| > is the best way of writing the original code because it clearly
| > shows the logic (as apposed to arithmetic) intent of the operation and
| > works for all cases the original works for.  The only reason for using
| > the original instead of this is if a must be 0 or 1 in the end, rather
| > than simply a false or true value.
|=20
| is there a case where 'a =3D not a' will yield a value other than 0 or
| 1?  i am not aware of one.

All boolean operations in CPython 2.3.  (see PEP 285)

It is also the case in Java (boolean operations return a 'boolean' not
an 'int') and probably C++ as well.

I know you are referring to current python implementations (eg CPython
1.5.2, 2.0, 2.1, 2.2), but it _is_ implementation dependent.  It is
never a good idea to rely on implementation dependent behavior if it
is avoidable.  IMO it is more obscure to use boolean operators when
arithmetic results are required.  Obscure code is not a good thing.

-D

--=20

Many a man claims to have unfailing love,
but a faithful man who can find?
        Proverbs 20:6
=20
GnuPG key : http://dman.ddts.net/~dman/public_key.gpg


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