How to search a list of Object by another list of items in dart

Question

How to search a list of a class object with one of its property matching to any value in another list of strings

I am able to get filtering based on a single string , bu

Answer 1

  List<SomeClass> list = list to search;
  List<String> matchingList = list of strings that you want to match against;

  list.where((item) => matchingList.contains(item.relevantProperty));

If the number of items in list is large, you might want to do:

  List<SomeClass> list = list to search;
  List<String> matchingList = list of strings that you want to match against;

  final matchingSet = HashSet.from(matchingList);

  list.where((item) => matchingSet.contains(item.relevantProperty));

Or else just always store the matching values as a hashset.

Answer 2

In case if you want to check for a value in a list of objects . you can follow this :

 List rows = [
          {"ags": "01224", "name": "Test-1"},
          {"ags": "01224", "name": "Test-1"},
          {"ags": "22222", "name": "Test-2"},
        ];
    
    bool isDataExist(String value) {
    var data= rows.where((row) => (row["name"].contains(value)));
      if(data.length >=1)
     {
        return true;
     }
    else 
     {
        return false;
     }
    }   

you can put your own array of objects on rows . replace your key with name . you can do your work based on true or false which is returned from the function isDataExist

Answer 3

 var one = [
    {'id': 1, 'name': 'jay'},
    {'id': 2, 'name': 'jay11'},
    {'id': 13, 'name': 'jay222'}
  ];

  int newValue = 13;

  print(one
      .where((oldValue) => newValue.toString() == (oldValue['id'].toString())));

OUTPUT : ({id: 13, name: jay222})

store output in any variable check if variable.isEmpty then new value is unique either

var checkValue = one
      .where((oldValue) => newValue.toString() == (oldValue['id'].toString()))
      .isEmpty;
  if (checkValue) {
    print('Unique');
  } else {
    print('Not Unique');
  }

OUTPUT : Not Unique

Answer 4

You can simply use List.where() to filter a list

final List<shop_cart.ShoppingCart> cartprd = snapshot.documents
      .where((f) => shop_cart.ShoppingCart.contains(f.data));

Answer 5

As of today, you can't.

(A side note : You can use .where, .singleWhere, .firstWhere. This site explains various list/array methods.)