(PHP 7 >= 7.1.0)
is_iterable — Verify that the contents of a variable is an iterable value
Verify that the contents of a variable is accepted by the iterable pseudo-type, i.e. that it is either an array or an object implementing Traversable
varThe value to check
   Returns TRUE if var is iterable, FALSE 
   otherwise.
  
Example #1 is_iterable() examples
<?php
var_dump(is_iterable([1, 2, 3]));  // bool(true)
var_dump(is_iterable(new ArrayIterator([1, 2, 3])));  // bool(true)
var_dump(is_iterable((function () { yield 1; })()));  // bool(true)
var_dump(is_iterable(1));  // bool(false)
var_dump(is_iterable(new stdClass()));  // bool(false)
?>