Flutter/Dart- Filter nested list-CodePudding

I want to filter out a list in Flutter/dart which has nested objects. I want to filter out the list based on the name property both with in the parent object and the child object subNames.

Below is the code that I have come up with, which gives me duplicates, is there a better way to solve this?

    var rawData = [{
            "name": "Testing 123",
            "subNames": [{
                "name": "Subtesting 123"
            }]
        },
        {
            "name": "Testing 456",
            "subNames": [{
                "name": "Subtesting 456"
            }]
        },
        {
            "name": "Testing 456",
            "subNames": []
        }
    ]
        
     final results = [
                ...rawData
                    .where((m) =>
                        m.name.toLowerCase().contains('subtesting 123'))// or Testing 123
                    .toList(),
                ...rawData
                    .where((m) => m.subNames
                        .where((s) =>
                            s.name.toLowerCase().contains('subtesting 123')) // or Testing 123
                        .isNotEmpty)
                    .toList()
              ];

Expected output:
//Results
[{
        "name": "Testing 123",
        "subNames": [{
            "name": "Subtesting 123"
        }]
    }, 
]

CodePudding user response：

First of all, it's better to use Class models and typed variables over json or dynamic nested types. Using this approach we can implement our logic easier. Here is a sample:

const rawData = [
  {
    "name": "Testing 123",
    "subNames": [
      {"name": "Subtesting 123"}
    ]
  },
  {
    "name": "Testing 456",
    "subNames": [
      {"name": "Subtesting 456"}
    ]
  },
  {"name": "Testing 456", "subNames": []}
];

class Model {
  String name;
  List<SubNames> subNames;

  Model({this.name, this.subNames});

  Model.fromJson(Map<String, dynamic> json) {
    name = json['name'];
    if (json['subNames'] != null) {
      subNames = <SubNames>[];
      json['subNames'].forEach((v) {
        subNames.add(new SubNames.fromJson(v));
      });
    }
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['name'] = this.name;
    if (this.subNames != null) {
      data['subNames'] = this.subNames.map((v) => v.toJson()).toList();
    }
    return data;
  }
}

class SubNames {
  String name;

  SubNames({this.name});

  SubNames.fromJson(Map<String, dynamic> json) {
    name = json['name'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['name'] = this.name;
    return data;
  }
}

void main() {
  List<Model> testModelList = rawData.map((e) => Model.fromJson(e)).toList();
  final result = testModelList.where((element) =>
      element.name.toLowerCase().contains('subtesting 123') ||
      element.subNames
          .any((sub) => sub.name.toLowerCase().contains('subtesting 123')));
  print('result.length : ${result.length}');
  result.forEach((element) {
    print(element.toJson());
  });
}

You can run this sample see the result.

CodePudding user response：

Try changing your results to the following

final results = [
  ...rawData
      .where((m) =>
          m.name.toLowerCase().contains('subtesting 123') 
            || m.subNames
          .where((s) =>
              s.name.toLowerCase().contains('subtesting 123')).toList().isNotEmpty)
      .toList(),
];

I'm assuming here you are parsing your rawData so you are able to use m.names instead of m['names']