php怎么实现数组随机且不重复

<?php
define(&#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);
    }
}
 
 
?>