Invalid argument supplied for foreach()
I usually use a construct similar to this:
/** * Determine if a variable is iterable. i.e. can be used to loop over. * * @return bool */function is_iterable($var){ return $var !== null && (is_array($var) || $var instanceof Traversable || $var instanceof Iterator || $var instanceof IteratorAggregate );}$values = get_values();if (is_iterable($values)){ foreach ($values as $value) { // do stuff... }}Note that this particular version is not tested, its typed directly into SO from memory.
Edit: added Traversable check