从现有数组按日期创建数组

Question

我有一系列物品。所有项目都包含start_date。

根据开始日期，我想创建一个新数组，从start_date作为键开始，然后是当天内的每个条目。

因此：

（json中的示例，原始数组更长，每天有多个条目）

[
        {
            "Booking_id": "135474",
            "Start_date": "2017-08-11 09:10:00",
            "End_date": "2017-08-11 09:59:00",
            "Max_participants": null,
            "Description": "Schedule Sports Hall 3",
            "Trainer": "1053",
            "Memo": null,
            "Cms_id": null,
            "Product_id": "85",
            "First_name": "Teri",
            "Middle_name": null,
            "Last_name": "Hatcher"
        },
        {
            "Booking_id": "133718",
            "Start_date": "2017-08-11 10:00:00",
            "End_date": "2017-08-11 10:59:00",
            "Max_participants": null,
            "Description": "Schedule Sports Hall 3",
            "Trainer": "1053",
            "Memo": null,
            "Cms_id": null,
            "Product_id": "85",
            "First_name": "Teri",
            "Middle_name": null,
            "Last_name": "Hatcher"
        },
        {
            "Booking_id": "135514",
            "Start_date": "2017-08-12 11:00:00",
            "End_date": "2017-08-12 11:59:00",
            "Max_participants": null,
            "Description": "Schedule Sports Hall 3",
            "Trainer": "1053",
            "Memo": null,
            "Cms_id": null,
            "Product_id": "85",
            "First_name": "Teri",
            "Middle_name": null,
                "Last_name": "Hatcher"
            }
]

我想这样做：

{
  "2017-08-11" : [ {
            "Booking_id": "135474",
            "Start_date": "2017-08-11 09:10:00",
            "End_date": "2017-08-11 09:59:00",
            "Max_participants": null,
            "Description": "Schedule Sports Hall 3",
            "Trainer": "1053",
            "Memo": null,
            "Cms_id": null,
            "Product_id": "85",
            "First_name": "Teri",
            "Middle_name": null,
            "Last_name": "Hatcher"
        },
        {
            "Booking_id": "133718",
            "Start_date": "2017-08-11 10:00:00",
            "End_date": "2017-08-11 10:59:00",
            "Max_participants": null,
            "Description": "Schedule Sports Hall 3",
            "Trainer": "1053",
            "Memo": null,
            "Cms_id": null,
            "Product_id": "85",
            "First_name": "Teri",
            "Middle_name": null,
            "Last_name": "Hatcher"
        }
],
"2017-08-12" => ,
        [{
            "Booking_id": "135514",
            "Start_date": "2017-08-12 11:00:00",
            "End_date": "2017-08-12 11:59:00",
            "Max_participants": null,
            "Description": "Schedule Sports Hall 3",
            "Trainer": "1053",
            "Memo": null,
            "Cms_id": null,
            "Product_id": "85",
            "First_name": "Teri",
            "Middle_name": null,
                "Last_name": "Hatcher"
            }]
   }

我不确定json是否准确，但我认为你明白了。我自己尝试了这个，但发现了一些性能问题，导致一切都耗时太长。