Conversion one dimensional array to two dimensional array in php?

Question

$stack = array(1,2,3,4,5,6,7,8,1,2,3,4,5,6,7,8);
$myarr = array(array(),array());
$order = 4;
$i = 1;
$j = 1;

foreach($stack as $value){

    $myarr[$i][$j] = $value;

    if($j % $order == 0){
        $j = 1;
        $i++;
    }else{
         $j++;   
    }


}

echo $myarr[1][2];

for ($i = 1; $i <= $order; $i++){
    for($j = 1; $j <= $order; $j++){

        echo $myarr[$i][$j];
        echo " ";

        if($j % $order == 0){
            echo "<br/>";
        }
    }
}

*I want to convert one dimensional array to two dimensional with the existing element in php. Seems some problem while retrieving element from two 2d array.

Assuming you are trying to creating 4*4 multi-dimensional array of $stack. correct?? — Yash Parekh
– Yash Parekh, Commented Apr 22, 2018 at 8:59

Joseph_J · Accepted Answer · 2018-04-23 07:46:06Z

2

I think you should use array_chunk();

$stack = array(1,2,3,4,5,6,7,8,1,2,3,4,5,6,7,8);

$split = 4;

$array = array_chunk($stack, $split);

print_r($array);

Will output:

Array
(
    [0] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 3
            [3] => 4
        )

    [1] => Array
        (
            [0] => 5
            [1] => 6
            [2] => 7
            [3] => 8
        )

    [2] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 3
            [3] => 4
        )

    [3] => Array
        (
            [0] => 5
            [1] => 6
            [2] => 7
            [3] => 8
        )

)

UPDATED If your goal is to convert an array to a matrix then here is a solution. The solution also has a way to display the matrix as a matrix.

 function arrayToMat($array, $split){

  if(count($array) % $split == 0){

    $row = 1;

    for($i = 0; $i < count($array); $i += $split){

      for($j = 0; $j < $split; $j++){

        $mat[$row][$j+1] = $array[$i+$j];

      }

    $row++;

    }

    return $mat;

  } else {

  return FALSE;

  }

}



function displayMat($mat){

  echo
  '<table>';

  for($i = 1; $i <= count($mat); $i++){

    echo
    '<tr>';

    for($j = 1; $j <= count($mat[$i]); $j++){

      echo
      '<td>' .
      $mat[$i][$j] .
      '</td>';

    }

    echo
    '</tr>';

  }

  echo
  '</table>' . '<br><br>';

}




$stack = array(1,2,3,4,5,6,7,8,1,2,3,4,5,6,7,8);

$split = 4;

$mat = arrayToMat($stack, $split); //Will output your desired matrix indexes starting at 1;
//Will return false if cannot form a matrix.

//Show array structure.  Indexes start at 1;
print_r($mat);

//Prints out as matrix.
displayMat($mat);

//Change up the splits.
$mat = arrayToMat($stack, 2); //8x2 
displayMat($mat);

$mat = arrayToMat($stack, 4); //4x4
displayMat($mat);

$mat = arrayToMat($stack, 6); //Returns False

$mat = arrayToMat($stack, 8); //2x8
displayMat($mat);

This will output:

//Indexes start at 1.
Array
(
    [1] => Array
        (
            [1] => 1
            [2] => 2
            [3] => 3
            [4] => 4
        )

    [2] => Array
        (
            [1] => 5
            [2] => 6
            [3] => 7
            [4] => 8
        )

    [3] => Array
        (
            [1] => 1
            [2] => 2
            [3] => 3
            [4] => 4
        )

    [4] => Array
        (
            [1] => 5
            [2] => 6
            [3] => 7
            [4] => 8
        )

)

1   2   3   4
5   6   7   8
1   2   3   4
5   6   7   8

//8x2
1   2
3   4
5   6
7   8
1   2
3   4
5   6
7   8

//4x4  
1   2   3   4
5   6   7   8
1   2   3   4
5   6   7   8

//False with a split of 6

//2x8
1   2   3   4   5   6   7   8
1   2   3   4   5   6   7   8

edited Apr 23, 2018 at 7:46

answered Apr 22, 2018 at 9:01

Joseph_J

3,6692 gold badges15 silver badges22 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Aman Kumar Over a year ago

But I have to display it in the form of Matrix and and every element should be selected by it's row and column values to that I can make some operation on particular elements.

Joseph_J Over a year ago

@Aman Kumar Can you please post in your question an actual example of what it is you need. Displaying something as a matrix is different than handling something as a matrix. This array is essentially a matrix, it holds 4 rows and each row has four columns. Please just post a better example in your question. Thanks

Joseph_J Over a year ago

@Aman Kumar Please see updated answer, I think it will sufficiently answer your question. Don't forget to mark as the accepted answer, Cheers!

Collectives™ on Stack Overflow

Conversion one dimensional array to two dimensional array in php?

1 Answer 1

3 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related