Question

I have the following result from a MySQL query with two joins.

Array ( 
[0] => Array ( [place_id] => 1 [place] => Berlin [lat] => 52.519 [lon] => 13.406 [id] => 1 [pname] => Firstschool [typ] => 0 [s_id] => 32 [fac] => history) 

[1] => Array ( [place_id] => 1 [place] => Berlin [lat] => 52.519 [lon] => 13.406 [id] => 1 [pname] => Secondschool [typ] => 0 [s_id] => 33 [fac] => math)

[2] => Array ( [place_id] => 1 [place] => Berlin [lat] => 52.519 [lon] => 13.406 [id] => 1 [pname] => Secondschool [typ] => 0 [s_id] => 33 [fac] => english)
)

The data is redundant at some points, I need it this way:

Array ( 
  [Berlin] => Array ( [lat] => 52.519 
                      [lon] => 13.406  
                      [schools] => Array([0]=> Firstschool [1]=>Secondschool)
  )

  [OtherCity] => Array ( ... )
)

First, is this okay or exists a better solution? =)
Second.. how to split it for the needed result.

I tried it with something like the following code snippet, but it doesn’t work as wished.

foreach($viewmodel as $item) { 
   $data[$item['place']][] = $item['pname'];
}

The result is:

Array ( [Berlin] => Array ( [0] => Firstschool [1] => Firstschool [2] => Firstschool ))

NOT so useful. 😉

I hope its understandable what I need. Maybe someone has an nice idea how to solve this problem.

Thanks for your time.

Answer 1

I think you are on a right path, just need to fill in a little more detail:

$cities = Array (
     Array ( 'place_id' => 1, 'place' => 'Berlin', 'lat' => 52.519, 'lon' => 13.406, 'id' => 1, 'pname' => 'Firstschool', 'typ' => 0, 's_id' => 32, 'fac' => 'history'),
     Array ( 'place_id' => 1, 'place' => 'Berlin', 'lat' => 52.519, 'lon' => 13.406, 'id' => 1, 'pname' => 'Secondschool', 'typ' => 0, 's_id' => 33, 'fac' => 'math'),
     Array ( 'place_id' => 1, 'place' => 'Berlin', 'lat' => 52.519, 'lon' => 13.406, 'id' => 1, 'pname' => 'Secondschool', 'typ' => 0, 's_id' => 33, 'fac' => 'english'),
);

// gather the transformed array in a new array 
$out = array();
foreach ($cities as $city) {
    // the first time we see the place
    if (!isset($out[$city['place']])) {
        // copy over what you want to keep
        $out[$city['place']] = array(
            'lat' => $city['lat'],
            'lon' => $city['lon'],
            'schools' => array($city['pname']),
        );
    } // only add $city['pname'] if we don't have it already
    elseif (!in_array($city['pname'], $out[$city['place']]['schools'])) {
        // we already seen this place, just add to the schools
        $out[$city['place']]['schools'][] = $city['pname'];
    }
}

---

For the gather faculties too question, use the school names as keys to arrays in the ‘schools’ key of the top level arrays, populate them like this: (still skipping duplicates):

foreach ($a as $city) {
    if (!isset($out[$city['place']])) {
        $out[$city['place']] = array(
            'lat' => $city['lat'],
            'lon' => $city['lon'],
            'schools' => array($city['pname'] => array($city['fac'])),
        );
    } else {
        // for convenience and readability, introducing some variables
        $schools = &$out[$city['place']]['schools'];
        $pname = $city['pname'];
        $fac = $city['fac'];

        // if we didn't see this school yet, add it with it's faculty
        if (!isset($schools[$pname])) {
            $schools[$pname] = array($fac);
        } // if we did see this school before but the faculty is new, add it under the school's key
        else if (!in_array($fac, $schools[$pname])) { 
            $schools[$pname][] = $fac;
        }
    }
}