分享php生成不重复随机数、数组的4种方法

<?phpdefine(&#39;RANDOM_MAX&#39;, 100);define(&#39;COUNT&#39;, 10);
echo &#39;max random num: &#39;.RANDOM_MAX, &#39; ;result count:&#39;.COUNT, &#39;<br/>&#39;;
invoke_entry(&#39;rand1&#39;);invoke_entry(&#39;rand2&#39;);invoke_entry(&#39;rand3&#39;);invoke_entry(&#39;rand4&#39;);
function invoke_entry($func_name) { $time = new time(); $time->time_start(); call_user_func($func_name); echo $func_name.&#39; time spend: &#39;, $time->time_spend(); echo &#39;<br/>&#39;;}function rand1() { $numbers = range (1, RANDOM_MAX); shuffle($numbers); //随机打乱数组 $result = array_slice($numbers, 1, COUNT); return $result;}function rand2() { $result = array();  while(count($result)< COUNT) {  $result[] = mt_rand(1, RANDOM_MAX); //mt_rand()是比rand()更好更快的随机函数  $result = array_unique($result); //删除数组中重复的元素 } return $result;}function rand3() { $result = array();    while(count($result) < COUNT) {  $_tmp = mt_rand(1, RANDOM_MAX);  if(!in_array($_tmp, $result)) { //当数组中不存在相同的元素时，才允许插入   $result[] = $_tmp;  } }    return $result;}function rand4() { $result = array(); while (count($result) < COUNT) {  $result[] = mt_rand(1, RANDOM_MAX);  $result = array_flip(array_flip($result)); //array_flip将数组的key和value交换 } return $result;}class time { private $_start;  public function time_start() {  $this->_start = $this->microtime_float(); } public function time_spend() {  return $this->microtime_float() - $this->_start; } private function microtime_float() {  list($usec, $sec) = explode(" ", microtime());  return ((float)$usec + (float)$sec); }}
?>