How to Generate Random Numbers?

Hi guys, i have this number, 878777886XXXXXX. The Xs represent random numbers that I want to generate. I want to generate 1000 numbers that does not repeat using php. can anyone help?

thanks!

We can but don't expect us to just give you the code. What exactly have you tried?

this

$arr_randoms = array();
$i = 0;
do {
$val = '878777886' . mt_rand(1,999999);
if (!array_key_exists($val, $arr_randoms)) {
$arr_randoms[] = $val;
$i ++;
}
}while($i < 1000);

would generate an array with 1000 unique, random, elements (stat start with 878777886).
maybe there is a shorter/faster way --> who improves or comes with a more performant alternative?