Remove empty and null value recursively from PHP array

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?

what about 'one' ? it should be removed or not?

Leandro Papasidero
– Leandro Papasidero

2015-02-18 05:57:13 +00:00
Commented Feb 18, 2015 at 5:57 — Leandro Papasidero
– Leandro Papasidero, Commented Feb 18, 2015 at 5:57

cuongle · Accepted Answer · 2015-02-18 05:54:01Z

2

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 !== '';
  }); 
}

answered Feb 18, 2015 at 5:54

cuongle

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2 Comments

JVK Over a year ago

thanks for the suggestion. I am sorry to say, that there was an error in my example. You may see, I added some values inside five and added other key six that has empty array. So in this case, six should be completely removed as it does not contain any non-empty and non-null value child. Similarly five should be removed. And the result should be as shown in my question.

JVK Over a year ago

I added this return $item !== null && $item !== '' && count($item) > 0;

grant sun · Accepted Answer · 2015-02-18 06:22:21Z

0

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.

answered Feb 18, 2015 at 6:22

grant sun

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