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List 省道分割/压缩列表_List_Flutter_Dart - Fatal编程技术网

List 省道分割/压缩列表

List 省道分割/压缩列表,list,flutter,dart,List,Flutter,Dart,这是我的列表的代码: Future<List<Map>> queryDb() async { List localList; final db = await database; final allRows = await db.query(TABLE_FAVORITE); localList = allRows.toList(growable: true); localList.removeWhere((item) =

这是我的列表的代码:

      Future<List<Map>> queryDb() async {
    List localList;
    final db = await database;
    final allRows = await db.query(TABLE_FAVORITE);
    localList = allRows.toList(growable: true);
    localList.removeWhere((item) => item[COLUMN_ISFAVORITE] == 0);
    publicFavoriteList = localList;
    print(localList);
    return localList;
}
我怎样才能把这个“切”到


使用
map
从内部
map
对象中提取值:

var localValues=localList.map((o)=>o['id']as int.toList();
打印(本地值);
//打印:[0,1,2,4]

我想不可能是这样的。因为{}花括号需要键和值。@KuKu
{}
可以是映射(键和值)或集合(仅值)。不管怎样,我认为OP只是想要一个这些值的列表,而不是将每个值包装在一个完全冗余的集合中。
[{id: 0, isFavorite: 1}, {id: 1, isFavorite: 1}, {id: 2, isFavorite: 1}, {id: 4, isFavorite: 1}]
[{0}, {1}, {2}, {4}]