Re: logic operands problem
| From: | Peter Ford | Date: | Mon, 07 Dec 2009 11:19:38 +0000 |
| Subject: | Re: logic operands problem | ||
| References: | 1 | Groups: | php.general |
| Request: | Send a blank email to php-general+get-300268@lists.php.net to get a copy of this message | ||
Merlin Morgenstern wrote:
> Hello everybody,
>
> I am having trouble finding a logic for following problem:
>
> Should be true if:
> page = 1 OR page = 3, but it should also be true if page = 2 OR page = 3
>
> The result should never contain 1 AND 2 in the same time.
>
> This obviously does not work:
> (page = 1 OR page = 3) OR (page = 2 OR page = 3)
>
> This also does not work:
> (page = 1 OR page = 3 AND page != 2) OR (page = 2 OR page = 3 AND page
> != 1)
>
> Has somebody an idea how to solve this?
>
> Thank you in advance for any help!
>
> Merlin
Surely what you need is xor (exclusive-or)
I can't believe a programmer has never heard of that!
(page==1 XOR page==2) AND page==3
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