Test for empty nested array

Question

I have the following array:

array(4) {
  [29] => NULL
  [31] => NULL
  [33] => NULL
  [35] => NULL
}

I would like to test all keys if all keys contain NULL values.

Answer 1

if(count(array_filter($input, 'is_null')) == count($input)) { 

}

should be what you are looking for :)

Answer 2

// need php version >= 5.3 or you need to define a function, or just use a loop to check.
if (!count(array_filter($your_array, function($var){return $var !== null}))) {
  // all values is null.
}