Question

How to convert a 2D coordinate into 1D index in PHP

Answer 1

$array2d = array(
        array( 1,  2,   3,  6,  0), 
        array(-5, -4,   0,  7,  9), 
        array( 1, 18, 100, 14,  6), 
        array( 9, 10,  27, 12, 13) );
         
$array1d = array(1, 2, 3, 6, 0, -5, -4, 0, 7, 9, 1, 18, 100, 14, 6, 9, 10, 27, 12, 13);
         
$cols = count($array2d[0]);
 
$i = 1;
$j = 3;
              
$index = $i * $cols + $j;
     
echo $index . "\n";

echo $array2d[$i][$j] . "\n";
echo $array1d[$index] . "\n";
     
 
 
 
 
/*
run:
 
8
7
7
 
*/

 

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