无法在CodeIgniter中向PHP数组添加数据

Question

I have a PHP array, actually a MySQL row constructed with CodeIgniter's Active Record.

So I have an array which var_dumps like this :

array (size=10)
  0 => 
    array (size=4)
      'user_id' => string '2' (length=1)
      'puzzle_id' => string '17' (length=2)
      'birth' => string '2014-01-26 16:08:25' (length=19)
  1 => 
    array (size=4)
      'user_id' => string '2' (length=1)
      'puzzle_id' => string '16' (length=2)
      'birth' => string '2014-01-26 02:07:05' (length=19)
  2 => .....

this is constructed like this :

$this->db->order_by("birth" , "desc");
$rows = $this->db->get("my_table" , $limit)->result_array();        
foreach($rows as $row)
{
    $row['testindex'] = "testvalue";
}
return $rows;

so why does my array NOT have the "testindex" indices ?

Thanks for any help !

Answer 1

Because that's not how PHP and foreach() in particular works.

$row in your code is a copy of the corresponding element in $rows, not the actual element. Modifying a copy doesn't modify the original.

You'd want to do this:

for ($i = 0, $c = count($rows); $i < $c; $i++)
{
    $rows[$i]['testindex'] = 'testvalue';
}