Snippets Math Functions
Math Functions
mt_array_rand
by: Will Fischer
|
September 28, 2002
Version: 1.0
Type: Function
Category: Math Functions
License: GNU General Public License
Description: Handy drop-in function to replace PHP's stock array_rand, but uses PHP's mt_srand and mt_rand functions. The Mersenne Twister is much more random, and 4 times faster than standard rand() functions.
<?php
/* mt_array_rand - adapted from fake_array_rand func by zak@php.net */
/* copyleft (c) 2002 Will Fischer <wfischer@silverfisch.net> */
function mt_array_rand($array, $num_req = 1)
{
/* Ensure that $num_req has a sane value */
$num_req > 0 or $num_req = 1;
$count = count ($array);
for ($n=0; $n < $num_req; ++$n)
{
/* Seed the thing, for versions < 4.2.0 */
mt_srand ((double) microtime() * 10000000);
$randval = mt_rand();
/* Use the random value to 'pick' an entry from the array */
/* Count the number of times that the entry is picked */
++$index[$randval % $count];
}
/* Loop through the array */
for ($n = 0; $n < $count; ++$n, next($array))
{
/* When we get to an entry that has been picked
Put the entry into an array for output
Don't forget to decrease the counter */
while ($index[$n])
{
$out[] = key ($array);
--$index[$n];
}
}
/* Return a string if only on random key was asked for, otherwise return an array */
return ($num_req == 1) ? $out[0] : $out ;
}
?>
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