How do I determine if an array is empty in PHP?

Question

I want to check that an array has no values or that the values in the array are empty. Can someone explain how to do this?

Answer 1

Someday I've learned very smart solution here on SO

if(!array_filter($array)) {
  //array contains only empty values
}

or even smarter one (if applicable):

if(!array_filter($array,'trim')) {
  //array contains only empty values
}