Question

Is there is any way to avoid duplication in random number generation .

I want to create a random number for a special purpose. But it’s should be a unique value. I don’t know how to avoid duplicate random number

ie, First i got the random number like 1892990070. i have created a folder named that random number(1892990070). My purpose is I will never get that number in future. I it so i have duplicate random number in my folder.

Answer 1

You can write a wrapper for mt_rand which remembers all the random number generated before.

function my_rand() {
        static $seen = array();
        do{                                                                                                                                                                                                    
                $rand = mt_rand();
        }while(isset($seen[$rand]));
        $seen[$rand] = 1;
        return $rand;
}