A php class that allows you to do functions across arrays of objects or arrays

ArrayMath.php

$am = new ArrayMath();
$am->options = array('a'=>'sum', 'b'=>'avg', 'c'=>'max', 'd'=>'min', 'e'=>'prod');
$result = array(
  array('a'=>1, 'b'=>2, 'c'=>3, 'd'=>5, 'e'=>2),
  array('a'=>2, 'b'=>3, 'c'=>4, 'd'=>6, 'e'=>3), 
  array('a'=>3, 'b'=>4, 'c'=>0, 'd'=>7, 'e'=>4)
);
print_r($am->run($result));

/* RETURNS
 stdClass Object
 (
    [a] => 6
    [b] => 3
    [c] => 4
    [d] => 5
    [e] => 24
)
*/
class ArrayMath {
  public $options;
  public $calls;

  function __construct() {
    $calls = array(
      'sum'  => array('walk'  => function($val, $curr) { return $curr + $val; }),
      'avg'  => array('first' => function($val) { return array('count'=>1, 'sum'=>$val); },
                      'walk'  => function($val, $curr) { $curr['count']++; $curr['sum'] += $val; return $curr; },
                      'last'  => function($val, $curr) { $curr['sum'] += $val; $curr['count']++; return $curr['sum'] / $curr['count'];} ),
      'max'  => array('walk'  => function($val, $curr) { return max($curr, $val); }),
      'min'  => array('walk'  => function($val, $curr) { return min($curr, $val); }),
      'prod' => array('walk'  => function($val, $curr) { return $curr * $val; })
    );
      
    $this->calls = $calls;
  }

  public function run($input) {
    if ( ! is_array($input) ) throw new Exception('input must be an array');
    $result = new stdclass;
   print_r($this->options); 
    foreach ($input as $index => $entry) {
      if ( is_array($entry) ) {
        $entry = (object) $entry;
      }
      foreach ($this->options as $prop => $call) {
        $fns = $this->calls[$call];
        if ( isset($entry->$prop) ) {
          $value = $entry->$prop;
          $func = $fns['walk'];
          if ( $index == 0 ) {
            $func = isset($fns['first']) ? $fns['first'] : function($val) { return $val; };
          } else if ( $index == count($input) - 1 && isset($fns['last']) ) {
            $func = $fns['last'];
          }
          $result->$prop = $func($value, isset($result->$prop) ? $result->$prop : null);
        }
      }
    }
    return $result;
  }
}