How can I remove empty array

Question

I have this code in php.

 public function display_children($parent,$level){
 try {
          $cmd = $this->connection->prepare('SELECT mem,pid from mytree where pid = ?');

          $cmd->execute(array($parent));



          while ( $row =  $cmd->fetch(PDO::FETCH_ASSOC)) {


               $rec[] = [['v' => $row['mem'], 'f' => $row['mem']], (string)$row['pid'], $row['mem']];


              $this->display_children($row['mem'], $level + 1);

          }

               echo json_encode(rec);
      }
      catch(PDOException $ex){
          return $ex->getMessage();
      }

  }

And this is the result in my ajax

[][][[{"v":"9","f":"9"},"7","9"],[{"v":"10","f":"10"},"7","10"]][][[{"v":"7","f":"7"},"5","7"],[{"v":"8","f":"8"},"5","8"]]

I want to remove those empty array to be like this.is it possible ?

[[{"v":"9","f":"9"},"7","9"],[{"v":"10","f":"10"},"7","10"],[{"v":"7","f":"7"},"5","7"],[{"v":"8","f":"8"},"5","8"]]

I tried to use this to remove the empty array but it failed to remove.

 $rec = array_filter($rec);

Thank you in advance.

I don't see anything in your code that would create those empty elements at the beginning of the array. — Barmar
– Barmar, Commented Dec 15, 2014 at 6:36

Benjamin · Accepted Answer · 2014-12-15 06:45:01Z

2

you can use array_filter to do this.

function filter($var){
  return !empty($var);
}

$array1 = array("a"=>null, "b"=>2, "c"=>3, "d"=>4, "e"=>5);

$newarray = array_filter($array1, "filter"));

result: Array ( [b] => 2 [c] => 3 [d] => 4 [e] => 5 )

answered Dec 15, 2014 at 6:45

Benjamin

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Comments

Alex Yashin · Accepted Answer · 2014-12-15 07:53:21Z

1

Try something like this:

public function display_children($parent,$level, $rec = array()){
    try {
        $cmd = $this->connection->prepare('SELECT mem,pid from mytree where pid = ?');

        $cmd->execute(array($parent));

        while ( $row =  $cmd->fetch(PDO::FETCH_ASSOC)) {

            $rec[] = [['v' => $row['mem'], 'f' => $row['mem']], (string)$row['pid'], $row['mem']];

            $rec = $this->display_children($row['mem'], $level + 1, $rec);
        }
    }
    catch(PDOException $ex){
        //return $ex->getMessage();
        return $rec;
    }

    return $rec;
}

First call:

echo json_encode(display_children(5, 0));

edited Dec 15, 2014 at 7:53

answered Dec 15, 2014 at 6:40

Alex Yashin

493 bronze badges

11 Comments

Benjamin Over a year ago

this cannot work, cause as soon as the while loop passes only once $exists is true

Alex Yashin Over a year ago

'echo json_encode' starts after the loop in topic. so it will display empty array in all cases. so we need to skip 'echo json_encode' if loop body is skipped.

ashTon Over a year ago

almost got it [[{"v":"9","f":"9"},"7","9"],[{"v":"10","f":"10"},"7","10"]][[{"v":"7","f":"7"},"5","7"],[{"v":"8","f":"8"},"5","8"]] but there is ][ near 10,it should like this [[{"v":"9","f":"9"},"7","9"],[{"v":"10","f":"10"},"7","10"],[{"v":"7","f":"7"},"5","7"],[{"v":"8","f":"8"},"5","8"]]

Benjamin Over a year ago

yes, but if i understand the question correctly the filds form the db can be empty and this results in empty array parts. You only checking if is ther any result from the db. And for this you can simply use if(!empty($rec)) instead of using a variable

Alex Yashin Over a year ago

I have added "if ($level > 1) echo ',';" to the answer if you use $level = 0 in first call. Please check.

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