Php – way to find out how “deep” a PHP array is


A PHP array can have arrays for its elements. And those arrays can have arrays and so on and so forth. Is there a way to find out the maximum nesting that exists in a PHP array? An example would be a function that returns 1 if the initial array does not have arrays as elements, 2 if at least one element is an array, and so on.

Best Answer

Here's another alternative that avoids the problem Kent Fredric pointed out. It gives print_r() the task of checking for infinite recursion (which it does well) and uses the indentation in the output to find the depth of the array.

function array_depth($array) {
    $max_indentation = 1;

    $array_str = print_r($array, true);
    $lines = explode("\n", $array_str);

    foreach ($lines as $line) {
        $indentation = (strlen($line) - strlen(ltrim($line))) / 4;

        if ($indentation > $max_indentation) {
            $max_indentation = $indentation;

    return ceil(($max_indentation - 1) / 2) + 1;