Flutter filter results based on string-CodePudding

I have array of data returning from local JSON file and I need to filter data base on items specific value.

Data sample

[
    {
      "verse": ".........",
      "topic": "A"
    },
    {
      "verse": ".........",
      "topic": "A"
    },
    {
      "verse": ".........",
      "topic": "A"
    },
    {
      "verse": ".........",
      "topic": "A"
    },
    {
      "verse": ".........",
      "topic": "B"
    },
    {
      "verse": ".........",
      "topic": "B"
    },
    ..........
]

Here for instance I want to get data with topic A only.

Code

readDataBaseData() async {
    String data =
    await DefaultAssetBundle.of(context).loadString("assets/db/my_file.json");
    final jsonResult = jsonDecode(data);

    List items = jsonResult['ID'];


    // need that filter here (before return).


    return items; // currently returns sample data above
}

Ideas?

CodePudding user response：

You have to iterate over your list, a one-liner to remove all entries where the topic is not equal to A would be:

items.removeWhere((item) => item["topic"] != "A");

You can also use retainWhere:

items.retainWhere((item) => item["topic"] == "A");