1. <?php 
2. $arr=array('a','b','c','d'); 
3. $result=array(); 
4. $t= getCombinationToString($arr, 1); 
5. print_r($t); 
6. $t= getCombinationToString($arr, 2); 
7. $t2= getunique($t); 
8. print_r($t2); 
9. $t= getCombinationToString($arr, 3); 
10. $t2= getunique($t); 
11. print_r($t2); 
12. $t= getCombinationToString($arr, 4); 
13. $t2= getunique($t); 
14. print_r($t2); 
15.   
16. functiongetunique($t){ 
17.     $t2=array(); 
18.     //print_r($t); 
19.     for($i=0;$i<count($t);$i++){ 
20.         $count_list=array_count_values($t[$i]); 
21.         $flag= 1; 
22.         <a href="/tags.php/foreach/" target="_blank">foreach</a>($count_listas$ck=>$cv){ 
23.             if($cv>1){ 
24.                 $flag= 0; 
25.                 break; 
26.             } 
27.         } 
28.         if($flag){ 
29.             sort($t[$i]); 
30.             $flag2= 1; 
31.             if($t2){ 
32.                 foreach($t2as$t2k=>$t2v){ 
33.                     if($t[$i]==$t2v){ 
34.                         $flag2= 0; 
35.                         break; 
36.                     } 
37.                 } 
38.             } 
39.             if($flag2){ 
40.                 $t2[] =$t[$i]; 
41.             } 
42.         } 
43.     } 
44.     return$t2; 
45. } 
46.   
47. functiongetCombinationToString($arr,$m) { 
48.     if($m==1) { 
49.      return$arr; 
50.     } 
51.     $result=array(); 
52.       
53.     $tmpArr=$arr; 
54.     unset($tmpArr[0]); 
55.     for($i=0;$i<count($arr);$i++) { 
56.         $s=$arr[$i]; 
57.         $ret= getCombinationToString(array_values($tmpArr), ($m-1),$result); 
58.           
59.         foreach($retas$row) { 
60.             //$result[] = $s . $row; 
61.             $temp=array(); 
62.             $temp[] =$s; 
63.             if(is_array($row)){ 
64.                 $temp=array_merge($temp,$row); 
65.             }else{ 
66.                 $temp[] =$row; 
67.             } 
68.             sort($temp); 
69.             $result[] =$temp; 
70.         } //phpfensi.com 
71.     } 
72.  return$result; 
73. } 
74.   
75. ?> 
76.  

出处：http://www.phpfensi.com/php/20180809/11067.html