$arr1 = array(
array
(
'id' => '1',
'city' => 'A.bad',
),
array
(
'id' => '2',
'city' => 'Pune',
),
array
(
'id' => '1',
'city' => 'Mumbai',
)
);
$result = array(
array(
'id'='1',
'city'='A.bad','Mumbai'
),
array(
'id'='2',
'city'='Pune'
)
);
Loop through the array and generate a new array
depending on the id
.You can try this -
$new = array();
foreach($arr1 as $array) {
$new[$array['id']]['id']= $array['id'];
// check if the city value set for that id
// if set the concatenate else set with the city name
$new[$array['id']]['city']= (isset( $new[$array['id']]['city'])) ? ($new[$array['id']]['city'] . ',' . $array['city']) : $array['city'];
}
If you are getting that data from database the you can group them in the query also.