max() on multidimensional array

Question

I've got an array of input data and I need to find the max and min values. The POST array could look like any of the following, depending on the options the user selected:

[a] => Array
(
    [0] => 2
)

[a] => Array
    (
        [0] => 2
        [1] => 4
        [2] => 7
    )
[a] => Array
    (
        [0] => 2
        [1] => 4
        [2] => Array
            (
                [0] => 7
            )

    )

I had it working by sorting the array and grab the min and max values when 'a' was always a single-dimensional array, but since we've added the option for it to be multidimensional I'm stuck.

This http://stackoverflow.com/questions/4497810/min-and-max-in-multidimensional-array — IsisCode, Jan 31 '12 at 00:15
Flatten the array first http://stackoverflow.com/questions/7011451/transaprently-flatten-an-array and then apply the `max()` function. — mario, Jan 31 '12 at 00:17
I thought about flattening it but didn't want to risk overwriting existing keys. Maybe I was going about it wrong — gandalf007, Jan 31 '12 at 00:22

score 2 · Accepted Answer · answered Jan 31 '12 at 00:15

I would use an Iterator: http://php.net/spl.iterators.php

function array_max($arr) {
  $max = null;

  foreach (new RecursiveIteratorIterator(new RecursiveArrayIterator($arr)) as $value) {
    if ($max === null || $value > $max) {
      $max = $value;
    }
  }
  return $max;
}

I think you can figure out how to do array_min() on your own.

max() on multidimensional array

1 Answers1