Function generating Unique Random Values Array - php

Question

As Mysql rand() is time consuming I am using alternate way using Mysql max() and PHP. I wrote this code for fetching random product_id's:
function RandomUniqueArray($min,$max,$limit){
$random_array = array();
if(isset($limit) && is_numeric($limit)){
for($i=0;$i<$limit;){
$rand_val = mt_rand($min, $max);
if(!in_array($rand_val, $random_array)){
$random_array[] = $rand_val;
$i++;
}
}
}
return $random_array;
}
This works fine as I want each time it gives different result set with different unique values but it takes 6.232 micro seconds.
Ohter I got by Google is:
$random_array = array_rand(array_fill($min,$max, true),$limit);
with takes only 0.101 microseconds but its result set is repeated means. Unique values array is fine but whole set is repeated. Why is it so???
I called both of these by one by one as
$random_array = RandomUniqueArray(1,64000,4);
And
$random_array = array_rand(array_fill(1,64000, true),4);
Thank you.

Answer 1

I made a script,that only takes ̣̣̣+- 4.5E-6.
Try it.
function randomValue($min,$max,$limit)
{
$array = Array();
$MAX = mt_rand($min,$max);
for($i = 0;$i < $limit;$i++)
{
$array[$i] = mt_rand($min,$MAX);
while( is_array($array[$i],$array) ) //To check if exist, if. Make new.
{
$array[$i] = mt_rand($min,$MAX);
}
}
return $array;
}