Getting only certain data from the list in the object list with linq-CodePudding

[
  {
    "_id": "",
    "at": IsoDate(2022-11-19 10:00:00),
    "areaId": 3,
    "data": [
      {
        "label": 1,
        "name": "a",
        "sec": 34,
        "x": 10.3,
        "y": 23.3
      },
      {
        "label": 1,
        "name": "a",
        "sec": 36,
        "x": 10.3,
        "y": 23.3
      }
      ]
  },
  {
    "_id": "",
    "at": IsoDate(2022-11-19 10:01:00),
    "areaId": 4,
    "data": [
      {
        "name": "a",
        "label": 1,
        "sec": 10,
        "x": 10.3,
        "y": 23.3
      },
      {
        "label": 2,
        "name": "b",
        "sec": 12,
        "x": 10.3,
        "y": 23.3
      }
      ]
  }
  ]

I have a data like above and I want to get the data of only objects with label=1 from this data with the help of linq.

In other words, 2 data should come from the data field of the areaId=3 object and 1 data from the field of the areaId=4 object.

The return type will be the same.

How can I do this with LINQ?

CodePudding user response：

// assuming your an array is filled with your JSON data.
var array = ... // the array
var filtered = array
    .SelectMany(a => a.Data)
    .Where(d => d.Label == 1);

With this code you will get only 3 data results 2 from the first and 1 from the second.

var array = ... // the array
// Only get base object (with areaId) containing at least 1 data with label = 1
var filtered = array
    .Where(a => a.Data.Any(d => d.Label == 1)); 
foreach(var item in filtered)
{
    foreach(var data in item.Data.Where(d => d.Label == 1))
    {
        var areaId = item.AreaId;
        var name = data.name;
       // ...
    }
}

CodePudding user response：

var array...
array = array
    .Select(arrayItem => new YourReturnType
    {
        AreaId = arrayItem.areaId,
        At = arrayItem.At,
        Data = arrayItem.Data.Where(dataItem => dataItem.Label == 1)
    });

The "YourReturnType" is the parent, I don't know whats the name in your code.