PHP

php rand vs mt_rand

// Since PHP7.1 rand() has become an alias of mt_rand()
// mt_rand() was supposed to be faster and more random than rand() in older PHP Versions
// That means you can use rand() instead of mt_rand() on newer Versions
<?php
  rand(1, 100);		// will generate a random number between 1 and 100
?>

php rand between 0 and 1

mt_rand() / mt_getrandmax();