如何计算PHP数组中的唯一值

Question

I am getting data from database in following format,I just want to get data,How many restaurant name (count) in which country,How can i do this ? How can i change following array/object in php ?

stdClass Object
(
    [_id] => 5ce405ced246f713b6256f3a
    [location] => stdClass Object
        (
            [country] => Kuwait
        )
    [employerDetails] => Array
        (
            [0] => stdClass Object
                (
                    [restraunt_name] => test1
                 )
        )

    [_id] => 5ce405ced246f713b6277373
    [location] => stdClass Object
        (
            [country] => Kuwait
        )
    [employerDetails] => Array
        (
            [0] => stdClass Object
                (
                    [restraunt_name] => test2
                 )
        )       
    ....
 )

Answer 1

As object can have same keys I will assume you have array of object for each restaurant object.

First I recommend get only the countries to separate array as:

foreach($objectArray as $restaurant)
    $countries[] = $restaurant->location->country;

Now you can use array-count-values to get number of object according the countries:

print_r(array_count_values($countries));

Answer 2

$countries = array();
//first get all countries list
foreach ($array as $data) {
    if (!in_array($data->location->country, $countries)) {
        array_push($countries, $data->location->country);
    }
}
//get restraunt county wise
foreach ($array as $key => $data) {
    //if (in_array($data->location->country, $countries)) {
    if (!empty($data->location->country) && !empty($data->employerDetails[0]->restraunt_name)) {
        $countries_f[$data->location->country][$key] = $data->employerDetails[0]->restraunt_name;
    }
    //}
}
//get count of restraunt in each ocuntry
foreach ($countries as $cnt) {
    echo 'count of' . $cnt = count($countries_f[$cnt]) . '<br />';
}

echo "<pre>";
print_r($countries_f);

die;