PHP - 在数组中达到某个值

Question

我使用的API向我发送了一个对象/数组（不确定）。 这是我使用print_out($arr)获取的信息：

Array
(
    [0] => Array
    (
        [callID] => 40
        [PairCallLegId] => 
        [CallsCount] => 4
        [LocalName] => 151204
        [RemoteName] => 15740
        [type] => 1
        [isOut] => 0
        [FirstName] => Boris
        [lastName] => Ostrovsky
        [AvgMos] => 3.7432666239999963
        [AvgQoe] => 
        [AvgPL] => 
        [AvgJitter] => 
        [AvgVideoQP] => 
        [AvgBDW] => 1200
        [AvgFrameRate] => 
        [AvgTotalPkt] => 102433.80945757998
        [AvgTotalBytes] => 
    )
)

我试图达到“CallsCount”中的值（应为4）

我试过用 $arr[0]["CallsCount"] 和 $arr["0"]["CallsCount"] 乃至 $arr[0]->CallsCount

无效。我每次都会Internal Server Error (500)。

我该怎么办？