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Posted by Jochem Maas on 10/20/63 11:19
Dotan Cohen wrote:
> On 6/21/05, Jochem Maas <jochem@iamjochem.com> wrote:
>
>>Dotan Cohen wrote:
>>
.....
>>
>>
>
> $items is a static file, that does not change over time. It just needs
that makes things easier :-)
> to be output in a reproducable 'random' order for different purposes.
> I looked over your suggested fuctions, but decided to try Marek's
> simpler seed solution first. And it worked for what I need, so I will
indeed his is most to the point!
> be going that route. But I very much appreciate your insight. Although
> complicated, it presents a different way of solving the same problem.
the idea I proposed was more of a way to genericly (spelling?!?) hook in different
'random' ordering mechanisms - Marek's suggestion for ordering could be implemented
as a callback function in my example. e.g.
<?php
$items = array(
/* |--char 7 */
"cherries",
"bananas",
"orangejuice",
"red apples",
"smelly fish",
"more bananas",
"ship full of bananas",
"tarantula",
"poisoned apple",
/* |--char 7 */
);
function permaRandom($items, $callback)
{
/* caching left as an exercise to the reader ;-/ */
if (is_callable($callback)) {
$items2 = /*($yes = gotcachedpermarandom($callback))
? getfromcache($callback)
: */call_user_func($callback, $items);
/* if ($yes) storeincache($callback, $items2); */
}
return $items2;
}
function sortAlphaChar7Random($items)
{
$keys = $items2 = array();
// assumption made that $item is a string
// and at least 7 chars long, oh and spaces
// wont do much good for the sorting probably..
foreach ($items as $k => $item) {
$keys[$k] = @$item{7};
}
asort($keys, SORT_LOCALE_STRING | SORT_STRING);
foreach ($keys as $k => $v) {
$items2[] = $items[$k];
}
return $items2;
}
function fixedShuffle1($items)
{
static $fixedSeed = 384884;
$keys = $items2 = array();
// not sure whether seeding like this is a good idea
// with regard to other, non-related code that relies
// on the random generator... but anyway!
foreach ($items as $k => $item) {
$keys[] = $k;
}
srand( $fixedSeed );
shuffle($keys);
// srand( rand() ); // crap 'fix'?
foreach ($keys as $k => $v) {
$items2[] = $items[$k];
}
return $items2;
}
var_dump(permaRandom($items, "sortAlphaChar7Random"),
permaRandom($items, "sortAlphaChar7Random"),
permaRandom($items, "fixedShuffle1"),
permaRandom($items, "fixedShuffle1"));
?>
> That in itself is interesting. I intend to play with it a little when
> I have some more time. Maybe I will find an advantage in your solution
there may be absolutely no advantage ;-)
I was mostly trying to cram as much learning material into the idea/example
as possible - kind of over engineering (in so far as you could call it engineering)
in order to show as many (hopefully) new ideas to who ever read it :-)
I'll be interested to know how you get on.
rgds,
Jochem
> that I may need some day! Thank you.
>
> Dotan
> http://english-lyrics.com/
> Song Lyrics
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