php从数组中随机选择若干不重复元素的方法

<?php
/*
 * $array = the array to be filtered
 * $total = the maximum number of items to return
 * $unique = whether or not to remove duplicates before getting a random list
 */
function unique_array($array, $total, $unique = true){
    $newArray = array();
    if((bool)$unique){
        $array = array_unique($array);
    }
    shuffle($array);
    $length = count($array);
    for($i = 0; $i < $total; $i++){
        if($i < $length){
            $newArray[] = $array[$i];
        }
    }
    return $newArray;
}
$phrases = array('Hello Sailor','Acid Test','Bear Garden','Botch A Job','Dark Horse',
    'In The Red','Man Up','Pan Out','Quid Pro Quo','Rub It In','Turncoat',
    'Yes Man','All Wet','Bag Lady','Bean Feast','Big Wig', 'Big Wig','Bear Garden'
    ,'All Wet','Quid Pro Quo','Rub It In');
print_r(unique_array($phrases, 1));
// Returns 1 result
print_r(unique_array($phrases, 5));
// Returns 5 unique results
print_r(unique_array($phrases, 5, false));
// Returns 5 results, but may have duplicates if
// there are duplicates in original array
print_r(unique_array($phrases, 100));
// Returns 100 unique results    
print_r(unique_array($phrases, 100, false));
// Returns 100 results, but may have duplicates if
// there are duplicates in original array