compound conditional statements

[beliavsky@aol.com]

If I have code

if (aa or bb): print "true",

does Python evaluate aa and bb in any particular order? Can I assume that if
aa is true, bb will not be evaluated?

[Jeremy Yallop]

Re: compound conditional statements

beliavsky@aol.c om wrote:[color=blue]
> If I have code
>
> if (aa or bb): print "true",
>
> does Python evaluate aa and bb in any particular order?[/color]

Yes. `aa' is evaluated first. If it is true, `bb' is not evaluated
and the value of `aa' is the value of the expreesion. If `aa' is
false, the value of `bb' is the value of the expression.
[color=blue]
> Can I assume that if aa is true, bb will not be evaluated?[/color]

Yes.

Jeremy.

[Jeff Epler]

Re: compound conditional statements

On Mon, Sep 15, 2003 at 02:31:06PM -0700, beliavsky@aol.c om wrote:[color=blue]
> If I have code
>
> if (aa or bb): print "true",
>
> does Python evaluate aa and bb in any particular order? Can I assume that if
> aa is true, bb will not be evaluated?[/color]

Yes.

For more information, read the language reference:

http://python.org/doc/ref/Booleans.html

The expression x or y first evaluates x; if x is true, its value is
returned; otherwise, y is evaluated and the resulting value is
returned.

Jeff

[Steve Holden]

Re: compound conditional statements

<beliavsky@aol. com> wrote ...[color=blue]
> If I have code
>
> if (aa or bb): print "true",
>
> does Python evaluate aa and bb in any particular order? Can I assume that[/color]
if[color=blue]
> aa is true, bb will not be evaluated?[/color]

Yes. Both "and" and "or" are specifcally short-circuiting.

regards
--
Steve Holden http://www.holdenweb.com/
Python Web Programming http://pydish.holdenweb.com/pwp/