Converting 1D array to 2D array PHP

Question

I currently have a text file that looks like this:

0000001
0000002
0000003
0000004
0000005
0000006....

I am using the code below to convert 1d array to 2d..

$filename  = "surface.txt";
$fp = fopen($filename, "r");
while(!feof($fp)) {  
     $content = fread($fp, filesize($filename));
     $lines = explode("\n", $content);
   for ($i=0; $i<=$row; $i++){
   for ($j =0; $j<=$col; $j++){
      //echo $lines[$i*$col + $j]; 
      $matrix[$i][$j] = $lines[$i*$col + $j];
      //var_dump($matrix[i][j]); 
     }
    }
   }
 fclose($fp);

My output array $matrix prints all NULL values.I have put var_dump() inside the loop to see what it displays.. Interestingly, It is reading all the values,but, after the last value, it kept on reading empty values too, which inturn made the $matrix empty(NULL) at last. I don't know how to fix this problem. If I am not clear in explaining how the output appears, please look at it below..

Array ( [0] => Array ( [0] => 0000001 ) )
Array ( [0] => Array ( [0] => 0000002 [1] => 0000002 ) )
Array ( [0] => Array ( [0] => 0000001 [1] => 0000002 [2] => 0000003 ) )

In the last lines, I see that the output is like below

  Array ( [0] => Array ( [0] => [1] => [2] => [3] => ) [1] => Array ( [0] => [1] => [2] =>   [3] => ) [2] => Array ( [0] => [1] => [2] => [3] => ) [3] => Array ( [0] => [1] => [2] => [3] => ) [4] => Array ( [0] => [1] => [2] => [3] => ) [5] => Array ( [0] => [1] => [2] => [3] => ) [6] => Array ( [0] => [1] => [2] => [3] => ) )

Any help is highly appreciated..

Answer 1

<?php
//asuming $row and $col are defined
//$row=5;
//$col=5;


$filename  = "surface.txt";

     $content = file_get_contents($filename);
     $lines=explode("\n",$content);
foreach ($lines as $rowNum=>$r)
{
$r=str_split($r);
if ($rowNum+1>$row)
break;    
if ($r===[""])
continue;
while (count($r)>$col)
{
array_pop($r);
}
$matrix[]=$r;
}
var_dump($matrix);

Answer 2

Here is how I got it to work

  $filename="surface.txt"
 $fp = fopen($filename, "r");
 $content = fread($fp, filesize($filename));
 $lines = explode("\n", $content);
 for ($i=0; $i<$row; $i++){
 for ($j =0; $j<$col; $j++){

  $matrix[$i][$j] = $lines[$i*$col + $j];
 }
 }