Question

If I have an array like this:

array(2) {
  [0]=>
  array(2) {
    ["id"]=>
    string(2) "34"
    ["total"]=>
    string(6) "122337"
  },
[1]=>
  array(2) {
    ["id"]=>
    string(2) "43"
    ["total"]=>
    string(6) "232337"
  }
}

And I want to add a new key value to each sub array, so for example, it would end like this:

array(2) {
      [0]=>
      array(2) {
        ["id"]=>
        string(2) "34"
        ["total"]=>
        string(6) "122337"
        ["newkey"]=>
        string(6) "hihihi"
      },
    [1]=>
      array(2) {
        ["id"]=>
        string(2) "43"
        ["total"]=>
        string(6) "232337"
       ["newkey"]=>
        string(6) "hihihi"
      }
    }

How would I do it?

I have tried with a foreach like this:

foreach($exterior_array as $inside_array) {
 $inside_array['newkey'] = "hihihi";
}

But once I get inside the foreach, the values are not saved.

Answer 1

foreach($exterior_array as $inside_array) {
    $inside_array['newkey'] = "hihihi";
}

But once I get inside the foreach, the values are not saved.

That is because you are working on a copy of the array via $inside_array. You can access the “orignal” value you want to change by making $inside_array an alias of the origina value; using a reference:

foreach($exterior_array as &$inside_array) {
                           ^- set the reference
    $inside_array['newkey'] = "hihihi";
}
unset($inside_array);
^^^^^^^^^^^^^^^^^^^^^- remove the reference

Compare with http://php.net/foreach