How to search for the maximum value in a multidimensional array in a given range

Question

I have a multidimensional $array that has a lot of various values. I am trying to get the maximum value in a given range in this case lets say the maximum value within x1,y0 and x2,y7, thus the result would be 6 using the data below.

It seems like a common problem for searching within coordinates in multidimensional array... but I cant find a simple solution and everything that I try to do seems to be rather extensive in the coding. I was wondering if there is a function that would allow me to search in this array using my criteria in an efficient way.

$array[0][0] = 1;
$array[0][1] = 10;
$array[0][3] = 3;
$array[1[0] = 1;
$array[1][1] = 1;
$array[2][5] = 6;

Answer 1

$max = null;
for ($x = $startx; $x <= $endx; $x++) {
    for ($y = $starty; $y <= $endy; $y++) {
        if (isset($array[$x][$y]) && ($max === null || $array[$x][$y] > $max)) {
            $max = $array[$x][$y];
        }
    }
}

Answer 2

$array[0][0] = 1;
$array[0][1] = 10;
$array[0][3] = 3;
$array[1][0] = 1;
$array[1][1] = 1;
$array[2][5] = 6;

$max = false;
$x1 = 1; $x2 = 2;
$y1 = 0; $y2 = 7;

foreach($array as $x => $y_vals) {    
    if($x < $x1 || $x > $x2)
        continue;

    foreach($y_vals as $y => $val) {
        if($y < $y1 || $y > $y2)
            continue;

        if(false === $max || $max < $val)
            $max = $val;
    }
}

print $max; //6

Answer 3

$array[0][0] = 1;
$array[0][1] = 10;
$array[0][3] = 3;
$array[1][0] = 1;
$array[1][1] = 1;
$array[2][5] = 6;

$vals = array();
foreach (new RecursiveIteratorIterator(
             new RecursiveArrayIterator($array),
             RecursiveIteratorIterator::LEAVES_ONLY
         ) as $value) {
    $vals[] = $value;
}
$max = max($vals);
echo $max;