flutter - Dart list gives result separately

Question

When performing a calculation inside a list , it returns the results as separate list for every calculation.

List<int> amountCustom = [
  json.price *
      (cart.toSet().toList().map((value) {
        return [
          value,
          cart.where((element) => element == value).toList().length
        ];
      }).toList()[i][1]),
];

what this does is this calculates the item price with the number of repetation and shows the result.

This above code returns this result:

    I/flutter (13940): [28]
    I/flutter (13940): [88]
    I/flutter (13940): [1365]

But the problem is it performs and returns the numbers separately which dosen't let me add them up.

What I want is like this: List = [28,88,1365] all in a single list, so I could perform

List.reduce((a,b)=> a+b);

and obtain a result of 1481

question from:https://stackoverflow.com/questions/65644043/dart-list-gives-result-separately

Answer 1

var sum = cart
    .toSet()
    .toList()
    .map((value) {
      return [value, cart.where((element) => element == value).toList().length];
    })
    .map((e) => json.price * e[1])
    .reduce((a, b) => a + b);