Посчитать содержимое массива

      Array
(
    [0] => Array
        (
            [id] => 2
            [quanty] => 2
        )
    [1] => Array
        (
            [id] => 2
            [quanty] => 2
        )
    [2] => Array
        (
            [id] => 4
            [quanty] => 2
        )
)

$input = array(
    array('id'=>2, 'quanty'=>2),
    array('id'=>4, 'quanty'=>2),
    array('id'=>2, 'quanty'=>2),
);
$sum = array();
for($i = 0; $i < count($input); $i++) {
    if(isset($sum[$input[$i]['id']])) {
        $sum[$input[$i]['id']] += $input[$i]['quanty'];
    } else {
        $sum[$input[$i]['id']] = $input[$i]['quanty'];
    }
}
print_r($sum);

$arr = [
    [
        'id' => 2,
        'quantity' => 2
    ],
    [
        'id' => 2,
        'quantity' => 2
    ],
    [
        'id' => 4,
        'quantity' => 2
    ],
];
$arr2 = [];
array_walk($arr, function ($item) use (&$arr2){
    @$arr2[$item['id']] += $item['quantity'];
});
foreach ($arr2 as $key => $val) {
    echo 'id - ' . $key . ' = ' . $val . PHP_EOL;
}

<?php
      $data=array(
    "0" => array(
            "id" => "2",
            "quanty" => "2"
        ),
    "1" => array(
            "id" => "2",
            "quanty" => "2"
        ),
    "2" => array(
            "id" => "4",
            "quanty" => "2"
        )
);
      foreach ($data as $key => $value) {
        $eniq[]=$value["id"];
        $mass[$value["id"]]=$value["quanty"];
      }
      $res=array_count_values ($eniq);
foreach ($mass as $key1 => $value1) {
    foreach ($res as $key2 => $value2) {
                                            if($key1==$key2){
$bin[$key1]=$value1*$value2.'шт';
        }
    }
}
print_r($bin);
?>