php - Pair all elements between them without duplicates -

at point script working not fully. managed pair elements without duplicates, cant seem find way repeat loop can possible results. 20 possible results 16 19 results. appreciated. here's long code + output

$studentlist = array     (     array('up1','up2','up3','up4','up5','up6', 'up7', 'up8' , 'up9' , 'up10'),     array('up1','up2','up3','up4','up5','up6', 'up7', 'up8' , 'up9' , 'up10'),     array('up1','up2','up3','up4','up5','up6', 'up7', 'up8' , 'up9' , 'up10'),     ); //count how many times user wants pair students $ac = count($studentlist);  //take away 1 count due first aray used setting pairs $ac--;  //count how may users need paired $c = count($studentlist[0]); $totalcount = $ac * $c; echo $totalcount."<= total count<br>";   ($b = 1; $b <= $ac; $b++) {     shuffle($studentlist[$b]);     print_r ($studentlist[$b]);     echo"<br>"; } $z = 0; $r = 1; $flagreset = 0; //this make sure results random ($i = 0; $i < $totalcount; $i++) {        if ($studentlist[0][$z] == $studentlist[$r][$z]){}     else     {         $randomarray[$i] = $studentlist[0][$z] ."/".$studentlist[$r][$z];     }    //echo $z."<= z count|";    if ($i == 0)    {        echo "i first $z / $c / $r <br>";    }            if ($z == $c - 1 )     {         if ($i < $totalcount -1 )         {             $r++;             $z= 0;             $flagreset = 1;         }         else          {             $flagreset = 1;         }     }      if ($flagreset == 1)     {         $flagreset = 0;     }      else     {         $z++;     }      if ($i == 19)     {         echo "i last $z / $c / $r <br>";     }             array_unique($randomarray, sort_regular);     $rand = count($randomarray); }  echo "<br>"; array_unique($randomarray, sort_regular); $rand = count($randomarray); print_r($randomarray); print $rand; 

output:

20<= total count array ( [0] => up8 [1] => up9 [2] => up2 [3] => up4 [4] => up5          [5] => up6 [6] => up3 [7]      => up10 [8] => up1 [9] => up7 )  array ( [0] => up4 [1] => up5 [2] => up8 [3] => up7 [4] => up6 [5] => up1          [6] => up2 [7]     => up9 [8] => up10 [9] => up3 )  first 0 / 10 / 1  last 9 / 10 / 2   array ( [0] => up1/up8 [1] => up2/up9 [2] => up3/up2 [6] => up7/up3          [7] => up8/up10 [8] => up9/up1 [9] => up10/up7 [10] => up1/up4          [11] => up2/up5 [12] => up3/up8 [13] => up4/up7 [14] => up5/up6          [15] => up6/up1 [16] => up7/up2 [17] => up8/up9 [18] => up9/up10          [19] => up10/up3 ) 17 

not anymore temporary answer, answer

from i've understood, you're trying find possible combinations 2 shuffled arrays of array $studentlist.

i've tried reading on , on code you've written, i'm not understanding why you're using many loops , flag.

what i've tried this:

    <?php         // stackoverflow test area         $studentlist = array         (         array('up1','up2','up3','up4','up5','up6', 'up7', 'up8' , 'up9' , 'up10'),         array('up1','up2','up3','up4','up5','up6', 'up7', 'up8' , 'up9' , 'up10'),         array('up1','up2','up3','up4','up5','up6', 'up7', 'up8' , 'up9' , 'up10')         ); //count how many times user wants pair students     $ac = count($studentlist);      //take away 1 count due first aray used setting pairs     $ac--;      //count how may users need paired     $c = count($studentlist[0]);     $totalcount = $ac * $c;     echo $totalcount."<= total count<br>";       ($b = 1; $b <= $ac; $b++)     {         shuffle($studentlist[$b]);         print_r ($studentlist[$b]);         echo"<br>";     }     $randomarray = array();     //this make sure results random     foreach ($studentlist[0] $value) {         foreach ($studentlist[1] $second_value) {             if ($value !== $second_value) {                 if (!in_array("{$value}/{$second_value}",$randomarray) , !in_array("{$second_value}/{$value}",$randomarray)) {                     $randomarray[] = "{$value}/{$second_value}";                 }             }         }     }     array_unique($randomarray, sort_regular);     $rand = count($randomarray);     print_r($randomarray);     print $rand; ?> 

the big deal here:

foreach ($studentlist[0] $value) {         foreach ($studentlist[1] $second_value) {             if ($value !== $second_value) {                 if (!in_array("{$value}/{$second_value}",$randomarray) , !in_array("{$second_value}/{$value}",$randomarray)) {                     $randomarray[] = "{$value}/{$second_value}";                 }             }         }     } 

i'm not understing why you're doing regular loop.

the goal basicly finding possible combinations, right? why not looping through both arrays , check if:

1. the values identical ( ignore in case ).
2. the values different.

in second case, there 2 possibilities:

1. the value x1/x2 or x2/x1 exists in array (ignore).
2. the value x1/x2 or x2/x1 doesn't yet exist. push it.

and result this:

20<= total count array ( [0] => up4 [1] => up10 [2] => up9 [3] => up6 [4] => up5 [5] => up7 [6] => up3 [7] => up8 [8] => up2 [9] => up1 )   array ( [0] => up10 [1] => up8 [2] => up6 [3] => up5 [4] => up7 [5] => up4 [6] => up1 [7] => up2 [8] => up3 [9] => up9 )   array ( [0] => up1/up4 [1] => up1/up10 [2] => up1/up9 [3] => up1/up6 [4] => up1/up5 [5] => up1/up7 [6] => up1/up3 [7] => up1/up8 [8] => up1/up2 [9] => up2/up4 [10] => up2/up10 [11] => up2/up9 [12] => up2/up6 [13] => up2/up5 [14] => up2/up7 [15] => up2/up3 [16] => up2/up8 [17] => up3/up4 [18] => up3/up10 [19] => up3/up9 [20] => up3/up6 [21] => up3/up5 [22] => up3/up7 [23] => up3/up8 [24] => up4/up10 [25] => up4/up9 [26] => up4/up6 [27] => up4/up5 [28] => up4/up7 [29] => up4/up8 [30] => up5/up10 [31] => up5/up9 [32] => up5/up6 [33] => up5/up7 [34] => up5/up8 [35] => up6/up10 [36] => up6/up9 [37] => up6/up7 [38] => up6/up8 [39] => up7/up10 [40] => up7/up9 [41] => up7/up8 [42] => up8/up10 [43] => up8/up9 [44] => up9/up10 ) 45 

am going wrong somewhere or you're looking for?