How to check if variable is array?... or something array-like

If you are using foreach inside a function and you are expecting an array or a Traversable object you can type hint that function with:

function myFunction(array $a)function myFunction(Traversable)

If you are not using foreach inside a function or you are expecting both you can simply use this construct to check if you can iterate over the variable:

if (is_array($a) or ($a instanceof Traversable))

foreach can handle arrays and objects. You can check this with:

$can_foreach = is_array($var) || is_object($var);if ($can_foreach) {    foreach ($var as ...}

You don't need to specifically check for Traversable as others have hinted it in their answers, because all objects - like all arrays - are traversable in PHP.

More technically:

foreach works with all kinds of traversables, i.e. with arrays, with plain objects (where the accessible properties are traversed) and Traversable objects (or rather objects that define the internal get_iterator handler).

(source)

Simply said in common PHP programming, whenever a variable is

• an array
• an object

and is not

• NULL
• a resource
• a scalar

you can use foreach on it.

You can check instance of Traversable with a simple function. This would work for all this of Iterator because Iterator extends Traversable

function canLoop($mixed) {    return is_array($mixed) || $mixed instanceof Traversable ? true : false;}