比较两个列表中的元素并在 Dart 中创建一个新列表

Question

我有两个列表，我想通过比较两个列表来创建一个新列表，新列表应该只包含每个列表中包含的元素。

List1=[[id: 1, label: 'cocoa'],[id: 2, label: 'apple'],[id: 3, label: 'cherry'],[id: 4, label: 'banana'],[id: 5, label: 'melon'],[id: 6, label: 'orange'],[id: 7, label: 'pineapple'],[id: 8], label: 'strawberry']
List2=[2,5,7,8]
expectedList = [[id: 2, label: 'apple'],[id: 5, label: 'melon'],[id: 7, label: 'pineapple'],[id: 8], label: 'strawberry']]

下面是真正的代码：

"options": [
                    {
                        "id": 58,
                        "label": "cocoa",
                        "swatch_value": null,
                        "products": [
                            118
                        ]
                    },
                    {
                        "id": 59,
                        "label": "dark chocolate",
                        "swatch_value": null,
                        "products": [
                            120,
                            127
                        ]
                    },
                    {
                        "id": 60,
                        "label": "apple",
                        "swatch_value": null,
                        "products": [
                            121,
                            128
                        ]
                    },
                    {
                        "id": 61,
                        "label": "milk",
                        "swatch_value": null,
                        "products": [
                            122
                        ]
                    },
                    {
                        "id": 62,
                        "label": "coconut",
                        "swatch_value": null,
                        "products": [
                            130
                        ]
                    },
                    {
                        "id": 65,
                        "label": "cherry",
                        "swatch_value": null,
                        "products": [
                            126
                        ]
                    }
                ]

所以第一个列表将包含上面的 json，第二个列表包含下面等于某些 ID 的数字。

List<int> secondList = [58, 59, 60, 61];

现在，当我想通过将 secondList 与第一个列表的 ID 进行比较来生成一个新列表时，第三个列表是空的。

List thirdList = firstList.options.where((element) => secondList.contains(element.id)).toList();

Answer 1

  var list1 = [1,2,3,4,5,6,7,8];
  var list2 = [2,5,7,8];
  var expectedList = list1.toSet().intersection(list2.toSet()).toList();

  print(expectedList.toString());

更多信息here。

尊重您的信息：

  var dataList = data['options'];
  var firstList = List<int>.generate(dataList.length, (i) => dataList[i]['id']);
  var secondList = [58, 59, 60, 61];
  var thirdList = firstList.toSet().intersection(secondList.toSet()).toList();
  var filtered = dataList.where((e) => thirdList.contains(e['id'])).toList();
  print(filtered.toString());

地点：

const data = {
  "options": [
...
  ]
};

结果是：

[{id: 58, label: cocoa, swatch_value: null, products: [118]}, {id: 59, label: dark chocolate, swatch_value: null, products: [120, 127]}, {id: 60, label: apple, swatch_value: null, products: [121, 128]}, {id: 61, label: milk, swatch_value: null, products: [122]}]