The upper-bound of this value is platform-independent. PHP implements the 32-bit version of the Mersenne Twister ("mt"), so the maximum possible value is 2**31 - 1 (2147483647).
(PHP 4, PHP 5, PHP 7)
mt_getrandmax — 显示随机数的最大可能值
返回调用 mt_rand() 所能返回的最大的随机数。
Example #1 计算一个随机浮点数
<?php
function randomFloat($min = 0, $max = 1) {
return $min + mt_rand() / mt_getrandmax() * ($max - $min);
}
var_dump(randomFloat());
var_dump(randomFloat(2, 20));
?>
以上例程的输出类似于：
float(0.91601131712832) float(16.511210331931)
The upper-bound of this value is platform-independent. PHP implements the 32-bit version of the Mersenne Twister ("mt"), so the maximum possible value is 2**31 - 1 (2147483647).