Merge arrays (PHP)

Question

How combine arrays in this way?

source:

Array
(
   [0] => Array
       (
           [id] => 3
           [title] => book
           [tval] =         


        

Answer 1

This should work:

$result = array();
foreach($array as $elem) {
    $key = $elem['id'];
    if (isset($result[$key])) {
        $result[$key]['tval'] .= ',' . $elem['tval'];
    } else {
        $result[$key] = $elem;
    }
}

This basically groups elements by id, concatenating tvals (separated by ,).

Answer 2

Simply building slightly on user576875's method:

$a = array ( 0 => array ( 'id' => 3,
                          'title' => 'book',
                          'tval' => 10000
                        ),
            1 => array  ( 'id' => 3,
                          'title' => 'book',
                          'tval' => 1700
                        ),
            3 => array  ( 'id' => 27,
                          'bcalias' => 'fruit',
                          'tval' => 3000
                        )
          );

$result = array();
foreach ($a as $elem) {
    $key = $elem['id'];
    if (isset($result[$key])) {
        $result[$key]['tval'] .= ',' . $elem['tval'];
    } else {
        $result[$key] = $elem;
    }
}
$result = array_merge($result);

var_dump($result);

gives a result of:

array
  0 => 
    array
      'id' => int 3
      'title' => string 'book' (length=4)
      'tval' => string '10000,1700' (length=10)
  1 => 
    array
      'id' => int 27
      'bcalias' => string 'fruit' (length=5)
      'tval' => int 3000

The only real difference is the array_merge() to reset the keys