PHP编程：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;
}
$phrases = array('Hello Sailor','Acid Test','Bear Garden','Botch A Job','Dark Horse',
??? 'In The Red','Man Up','Pan Out','Quid Pro Quo','Rub It In','Turncoat',
??? 'Yes Man','All Wet','Bag Lady','Bean Feast','Big Wig','Bear Garden'
???,'Rub It In');
print_r(unique_array($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