public static function verticalSlice($array, $field, $keyfield = null)
{
$array = (array) $array;
$R = array();
foreach ($array as $obj) {
if (!array_key_exists($field, $obj)) {
die("verticalSlice: array doesn't have requested field\n");
}
if ($keyfield) {
if (!array_key_exists($keyfield, $obj)) {
die("verticalSlice: array doesn't have requested field\n");
}
$R[$obj[$keyfield]] = $obj[$field];
} else {
$R[] = $obj[$field];
}
}
return $R;
}