From: "Jeff Lacy" <[EMAIL PROTECTED]>
> Hello Everyone,
>
> Could someone please explain the whole % thing? I sort of understand it,
> but not quite. My goal is to have a table, and have every row alternate
> between 4 colors. I can alternate sort of alternate between 3, but not
> quite. I have tried lots of different combinations, but I can't figure it
> out. Thank you very much!
% is the modulus operator, it tells you the remainder after dividing two
numbers.
For example, 5 % 4 will give you the remainder after 5 / 4, which is 1.
A common use for this is to check if a number is even or odd, by doing
modulus 2. E.g.
<?
function even_or_odd($number)
{
if ($number % 2) // if remainder is not 0
{
return "odd";
}
else // remainder is 0
{
return "even";
}
}
echo even_or_odd(4); // even
echo even_or_odd(13); // odd
?>
A practical application of that is inside a for-loop you increment a number
and return a different colour value depending on whether it's even or odd,
to give e.g. each row of a table an alternating background colour.
In your case if you want to alternate between four colours, all you need to
do is change to modulus 4 instead of modulus 2, i.e. $number % 4, and then
check if the remainder is 0, 1, 2 or 3.
>
>
> Maybe there should be a better link to it in the manual. The only one I
> could find was at http://www.php.net/manual/en/ref.math.php, but it is far
> from clear (to me at least....).
>
Well, this is a mathematical concept rather than PHP language-specific. :)
Cheers
Simon Garner
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