Javascript - 对列表进行分组和过滤答案

【问题标题】：Javascript - Grouping and filtering a list of listsJavascript - 对列表进行分组和过滤
【发布时间】：2022-06-20 11:28:25
【问题描述】：

我有一个值events，它是一个列表列表，其地图如下所示：

[
    [
        {
            "packageId": "2721",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 831,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        }
    ],
    [
        {
            "packageId": "2738",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 832,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        }
    ],
    [
        {
            "packageId": "2721",
            "eventTime": "2022-03-20T16:25:00Z",
            "type": "deviated-manually-overridden",
            "id": 842,
            "createdAt": "2022-03-20T16:26:00.363630Z",
            "createdBy": "47"
        },
        {
            "packageId": "2721",
            "eventTime": "2022-03-20T16:38:00Z",
            "type": "deviated-manually-overridden",
            "id": 844,
            "createdAt": "2022-03-20T16:38:46.352751Z",
            "createdBy": "47"
        },
        {
            "packageId": "2721",
            "eventTime": "2022-03-20T20:31:00Z",
            "type": "collected-manually-overridden",
            "id": 846,
            "createdAt": "2022-03-20T20:32:18.046346Z",
            "createdBy": "47"
        },
        {
            "packageId": "2721",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 829,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        }
    ],
    [
        {
            "packageId": "2738",
            "eventTime": "2022-03-20T16:25:00Z",
            "type": "deviated-manually-overridden",
            "id": 843,
            "createdAt": "2022-03-20T16:26:00.363630Z",
            "createdBy": "47"
        },
        {
            "packageId": "2738",
            "eventTime": "2022-03-20T16:38:00Z",
            "type": "deviated-manually-overridden",
            "id": 845,
            "createdAt": "2022-03-20T16:38:46.352751Z",
            "createdBy": "47"
        },
        {
            "packageId": "2738",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 830,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        }
    ],
    [
        {
            "packageId": "2721",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 833,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        }
    ],
    [
        {
            "packageId": "2738",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 834,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        }
    ]
]

我想通过地图的packageId 将这个列表分组到一个列表中，这样每个具有相同packageId 的地图都是一个列表的一部分。同时，我还想过滤掉具有相同packageId、type 和eventTime 的映射，这样我就只有一个具有相同字段值的映射。我想要实现的是：

[
    [
        {
            "packageId": "2721",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 831,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        },
        {
            "packageId": "2721",
            "eventTime": "2022-03-20T16:25:00Z",
            "type": "deviated-manually-overridden",
            "id": 842,
            "createdAt": "2022-03-20T16:26:00.363630Z",
            "createdBy": "47"
        },
        {
            "packageId": "2721",
            "eventTime": "2022-03-20T16:38:00Z",
            "type": "deviated-manually-overridden",
            "id": 844,
            "createdAt": "2022-03-20T16:38:46.352751Z",
            "createdBy": "47"
        },
        {
            "packageId": "2721",
            "eventTime": "2022-03-20T20:31:00Z",
            "type": "collected-manually-overridden",
            "id": 846,
            "createdAt": "2022-03-20T20:32:18.046346Z",
            "createdBy": "47"
        }
    ],
    [
        {
            "packageId": "2738",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 832,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        },
        {
            "packageId": "2738",
            "eventTime": "2022-03-20T16:25:00Z",
            "type": "deviated-manually-overridden",
            "id": 843,
            "createdAt": "2022-03-20T16:26:00.363630Z",
            "createdBy": "47"
        },
        {
            "packageId": "2738",
            "eventTime": "2022-03-20T16:38:00Z",
            "type": "deviated-manually-overridden",
            "id": 845,
            "createdAt": "2022-03-20T16:38:46.352751Z",
            "createdBy": "47"
        }
    ]
]

我不确定如何使用groupBy 或filter 实现这种数据结构。我试过了：

events.groupBy(listOfEvents => listOfEvents.map(e => e.get('packageId')))

但是，这显然行不通。我该怎么做？

更新：

我已尝试根据答案建议创建地图：

const grouped = Map<string, List<Event>>()
  events.map(list => list.map(event => {
    const packageId = event?.get('packageId')
    console.log('packageId ', packageId)
    if (packageId) {
      console.log('grouped packageId: ', grouped.get(packageId))
      if (!grouped.get(packageId)) {
        grouped.set(packageId, List<Event>())
      }
      const updatedList = grouped.get(packageId)?.push(event)
      console.log('updatedList: ', updatedList)
      if (updatedList) grouped.set(packageId, updatedList)
      console.log('grouped: ', grouped)
    }
  }))

  console.log('grouped ', grouped)

但是，这并没有在 Map 中设置任何值，我看到 packageId 已记录，但其他所有内容都是 undefined 和 grouped 的大小为 0。我在这里做错了什么？

【问题讨论】：

标签： javascript typescript immutable.js

【解决方案1】：

一种方法是使用packageId 作为键将所有内容传输到一个对象中，在此过程中，根据packageId、type 和eventTime 为每个对象生成一个id，如果是@，则忽略它987654326@ 已经被转移，然后将其值提取到数组中：

const data = [
    [
        {
            "packageId": "2721",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 831,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        }
    ],
    [
        {
            "packageId": "2738",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 832,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        }
    ],
    [
        {
            "packageId": "2721",
            "eventTime": "2022-03-20T16:25:00Z",
            "type": "deviated-manually-overridden",
            "id": 842,
            "createdAt": "2022-03-20T16:26:00.363630Z",
            "createdBy": "47"
        },
        {
            "packageId": "2721",
            "eventTime": "2022-03-20T16:38:00Z",
            "type": "deviated-manually-overridden",
            "id": 844,
            "createdAt": "2022-03-20T16:38:46.352751Z",
            "createdBy": "47"
        },
        {
            "packageId": "2721",
            "eventTime": "2022-03-20T20:31:00Z",
            "type": "collected-manually-overridden",
            "id": 846,
            "createdAt": "2022-03-20T20:32:18.046346Z",
            "createdBy": "47"
        },
        {
            "packageId": "2721",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 829,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        }
    ],
    [
        {
            "packageId": "2738",
            "eventTime": "2022-03-20T16:25:00Z",
            "type": "deviated-manually-overridden",
            "id": 843,
            "createdAt": "2022-03-20T16:26:00.363630Z",
            "createdBy": "47"
        },
        {
            "packageId": "2738",
            "eventTime": "2022-03-20T16:38:00Z",
            "type": "deviated-manually-overridden",
            "id": 845,
            "createdAt": "2022-03-20T16:38:46.352751Z",
            "createdBy": "47"
        },
        {
            "packageId": "2738",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 830,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        }
    ],
    [
        {
            "packageId": "2721",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 833,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        }
    ],
    [
        {
            "packageId": "2738",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 834,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        }
    ]
];
let groups = {};
for(let i = 0, filter = {}; i < data.length; i++)
{
  for(let j = 0; j < data[i].length; j++)
  {
    const d = data[i][j],
          id = d.packageId+"_"+d.type+"_"+d.eventTime;

    if (id in filter)
      continue;

    filter[id] = "";
    if (!groups[d.packageId])
      groups[d.packageId] = [];

    groups[d.packageId].push(d);
  }
}

groups = Object.values(groups);
console.log(groups);

附：这可以通过使用Array.map() 而不是for 循环在视觉上简化，但会稍微慢一些。

【讨论】：

我正在尝试将其转换为不可变的数据结构，例如，您将如何使用 Map 来做到这一点？

【解决方案2】：

试试这个

var grouped = {};
var lists = [
    [
        {
            "packageId": "2721",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 831,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        }
    ],
    [
        {
            "packageId": "2738",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 832,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        }
    ],
    [
        {
            "packageId": "2721",
            "eventTime": "2022-03-20T16:25:00Z",
            "type": "deviated-manually-overridden",
            "id": 842,
            "createdAt": "2022-03-20T16:26:00.363630Z",
            "createdBy": "47"
        },
        {
            "packageId": "2721",
            "eventTime": "2022-03-20T16:38:00Z",
            "type": "deviated-manually-overridden",
            "id": 844,
            "createdAt": "2022-03-20T16:38:46.352751Z",
            "createdBy": "47"
        },
        {
            "packageId": "2721",
            "eventTime": "2022-03-20T20:31:00Z",
            "type": "collected-manually-overridden",
            "id": 846,
            "createdAt": "2022-03-20T20:32:18.046346Z",
            "createdBy": "47"
        },
        {
            "packageId": "2721",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 829,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        }
    ],
    [
        {
            "packageId": "2738",
            "eventTime": "2022-03-20T16:25:00Z",
            "type": "deviated-manually-overridden",
            "id": 843,
            "createdAt": "2022-03-20T16:26:00.363630Z",
            "createdBy": "47"
        },
        {
            "packageId": "2738",
            "eventTime": "2022-03-20T16:38:00Z",
            "type": "deviated-manually-overridden",
            "id": 845,
            "createdAt": "2022-03-20T16:38:46.352751Z",
            "createdBy": "47"
        },
        {
            "packageId": "2738",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 830,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        }
    ],
    [
        {
            "packageId": "2721",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 833,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        }
    ],
    [
        {
            "packageId": "2738",
            "eventTime": "2022-03-15T11:24:12.200864Z",
            "type": "created",
            "id": 834,
            "createdAt": "2022-03-15T11:24:12.200864Z",
            "createdBy": "47"
        }
    ]
]

lists.map(list=>list.map(byPack=> {
   if (!grouped[byPack.packageId]){
       grouped[byPack.packageId]=[];
    }

    grouped[byPack.packageId].push(byPack);
}));

console.log(grouped);

【讨论】：

我已经更新了我的问题，努力用不可变的 Map 翻译这段代码，但我无法让它工作。您将如何使用不可变的 Map 来做到这一点？
lists.map... 块末尾缺少右括号