Permute an array of values.

<?php
    $arr = array(1,2,3,4,5);
    $perms = new permutation($arr);
    print_r($perms->results);   
?>

OUTPUT:
Array
(
    [0] => 12345
    [1] => 12354
    [2] => 12435
    [3] => 12453
    [4] => 12534
    [5] => 12543
    [6] => 13245
    [7] => 13254
    [8] => 13425
    [9] => 13452
    [10] => 13524
    [11] => 13542
    [12] => 14235
    [13] => 14253
    [14] => 14325
    [15] => 14352
    [16] => 14523
    [17] => 14532
    [18] => 15234
    [19] => 15243
    [20] => 15324
    [21] => 15342
    [22] => 15423
    [23] => 15432
    [24] => 21345
    [25] => 21354
    [26] => 21435
    [27] => 21453
    [28] => 21534
    [29] => 21543
    [30] => 23145
    [31] => 23154
    [32] => 23415
    [33] => 23451
    [34] => 23514
    [35] => 23541
    [36] => 24135
    [37] => 24153
    [38] => 24315
    [39] => 24351
    [40] => 24513
    [41] => 24531
    [42] => 25134
    [43] => 25143
    [44] => 25314
    [45] => 25341
    [46] => 25413
    [47] => 25431
    [48] => 31245
    [49] => 31254
    [50] => 31425
    [51] => 31452
    [52] => 31524
    [53] => 31542
    [54] => 32145
    [55] => 32154
    [56] => 32415
    [57] => 32451
    [58] => 32514
    [59] => 32541
    [60] => 34125
    [61] => 34152
    [62] => 34215
    [63] => 34251
    [64] => 34512
    [65] => 34521
    [66] => 35124
    [67] => 35142
    [68] => 35214
    [69] => 35241
    [70] => 35412
    [71] => 35421
    [72] => 41235
    [73] => 41253
    [74] => 41325
    [75] => 41352
    [76] => 41523
    [77] => 41532
    [78] => 42135
    [79] => 42153
    [80] => 42315
    [81] => 42351
    [82] => 42513
    [83] => 42531
    [84] => 43125
    [85] => 43152
    [86] => 43215
    [87] => 43251
    [88] => 43512
    [89] => 43521
    [90] => 45123
    [91] => 45132
    [92] => 45213
    [93] => 45231
    [94] => 45312
    [95] => 45321
    [96] => 51234
    [97] => 51243
    [98] => 51324
    [99] => 51342
    [100] => 51423
    [101] => 51432
    [102] => 52134
    [103] => 52143
    [104] => 52314
    [105] => 52341
    [106] => 52413
    [107] => 52431
    [108] => 53124
    [109] => 53142
    [110] => 53214
    [111] => 53241
    [112] => 53412
    [113] => 53421
    [114] => 54123
    [115] => 54132
    [116] => 54213
    [117] => 54231
    [118] => 54312
    [119] => 54321
)

The nature of the input allows you to pass either a string or an int into the function as a singular value:

<?php
     $arr = array('you','are','not','very','cool');
     $arr = array('you','are','#',1);
?>

I'd advise staying under 9 values, as the amount of permutations required is

aᵢ=i!

You can see a list of amounts here: http://www4d.wolframalpha.com/Calculate/MSP/MSP11619hfc32hdb0fb84f00002gb116g73ib5b7g0?MSPStoreType=image/gif&s=31&w=350&h=1008

class permutation {
    public $permutations = array();
    function __construct(array $arr) { $this->showPerms($this->permute($arr)); }
    private function showPerms($a,$i='') {
        if (is_array($a))
            foreach($a as $k => $v) 
                $this->showPerms($v,$i.$k);
        else 
            $this->results[] = $i.$a;
    }
    private function permute(array $arr) {
        $out = array();
        if (count($arr) > 1) 
            foreach($arr as $r => $c) {
                $n = $arr;
                unset($n[$r]);
                $out[$c] = $this->permute($n);
            }
        else
            return array_shift($arr);
        return $out;
    }       
}