Remove empty and null value recursively from PHP array - php

Question

I have an array like this
$a = array(
'b' => array(
'two' => false,
'three' => '',
'four' => null,
'five' => array(
'fp' => null,
'kp' => null
),
'six' => array()
),
'c' => ' ',
'd' => null
);
I want to remove only null and empty keys from this n-level array. And finally I should get this:
$a = array(
'b' => array(
'two' => false
),
'c' => ' '
);
I have this function
public function ArrayCleaner($input) {
foreach ($input as &$value) {
if (is_array($value)) {
$value = ArrayCleaner($value);
}
}
return array_filter($input);
}
But, as array_filter states, it will also remove false value key (that I want to preserve). So what change I should make in my function to achieve the expected result?

Answer 1

You are close, just change your code like below by providing the callback function for filtering:
function ArrayCleaner($input) {
foreach ($input as &$value) {
if (is_array($value)) {
$value = ArrayCleaner($value);
}
}
return array_filter($input, function($item){
return $item !== null && $item !== '';
});
}

Answer 2

function ArrayCleaner($input) {
foreach ($input as $key=>&$value) {
if(is_int($key)){
unset($input[$key]);
continue;
}
if (is_array($value)) {
$value = ArrayCleaner($value);
}
}
return array_filter($input, function($item){
return $item !== null && $item !== '';
});
}
But Question: what does empty key mean? 'one' indicates its index is number 0. So if we filter it by using something like is_int($key) , how to deal with '2'=>'this data?' ? it will convert to int(2) in php Array.