How do I check if array value is empty?

Question

Here is my array ouput

Array
(
    [1] => 1
    [2] => 2
    [3] =>  
)

How do I know the [3] => is empty?

Answer 1

im using in my project like this for check this array

im posting form data like this array('username' => 'john','surname' => 'sins');

public function checkArrayKeyExist($arr) {
    foreach ($arr as $key => $value) {
        if (!strlen($arr[$key])) {
            return false;
        }
    }
    return true;
}