Question

I have one main array which is the returned data from a MySQL query for user table which looks like this :

array(36) {
  [0]=>
  array(4) {
    ["id"]=>
    string(1) "101"
    ["email"]=>
    string(15) "[e-mail]"
    ["firstname"]=>
    string(8) "aaaaa"
    ["lastname"]=>
    string(12) "bbbbb"

  }
  [1]=>
  array(4) {
    ["id"]=>
    string(1) "102"
    ["email"]=>
    string(17) "[e-mail]"
    ["firstname"]=>
    string(12) "vvvv"
    ["lastname"]=>
    string(12) "zzzzz"

  }
  [2]=>
  array(4) {
    ["id"]=>
    string(2) "103"
    ["email"]=>
    string(17) "[e-mail]"
    ["firstname"]=>
    string(6) "ggggg"
    ["lastname"]=>
    string(12) "zzzzz"

And so on…
And a second array which is again MySQL query which is from a table with two foreign keys making relation b/w two table many to many and looks like this:

array(7) {
  [0]=>
  array(2) {
    ["user_id"]=>
    string(3) "101"
    ["group_id"]=>
    string(1) "1"
  }
  [1]=>
  array(2) {
    ["user_id"]=>
    string(3) "102"
    ["group_id"]=>
    string(1) "1"
  }
  [2]=>
  array(2) {
    ["user_id"]=>
    string(3) "103"
    ["group_id"]=>
    string(1) "1"
  }

The final goal is to make a 5th key in the first array, something like:

[“groups”]=>…

which i can populate with the id’s of the groups which every user takes part in and at the end to look like something like this:

[“groups”]=>”1,2,3,4″

In other words, because the relation is many to many the user may participate in more than one group when I push the new value I don’t want to create a new key with value but instead to concatinate the existing values of the key with the new id.

So far I got something like this:

$query = $this->mUsers->getAll(); //Main query to get users data
          $results = $this->mUsers->getGroupsAndUsers(); //Query for getting the group_id and user_id
        //  Looping both arrays to find matching ID's

          foreach($query as $key=>$value){ //$value['id'] returns the value of the users id from table users
              foreach($results as $row){
                  if ($value['id']==$row['user_id'])
               {
                          array_push($value,"groups",$row['group_id']);

                }

              } 

}

But I doesn’t work. I tried a few other things but nothing by now.

Thanks
Leron

Answer 1

It’s making your life more difficult, and making the data less useful, to try and construct a comma separated string. It makes much more sense to create a sub-array of values, which you can implode(',', $arr) if you need a string representation down the line. It also makes the job a lot easier, and the data more useable, if your array of user data has the same keys as the user_id field:

// First, get the array of users and format it with sensible keys
$users = array();
foreach ($this->mUsers->getAll() as $user) $users[$user['id']] = array_merge($user, array('groups' => array()));

// Now assign group relationships
foreach ($this->mUsers->getGroupsAndUsers() as $group) {
  $users[$group['user_id']]['groups'][] = $group['group_id'];
}

print_r($users);