Flutter:How to merge two objects and sum the values of the same key?-CodePudding

map1 = { "a": 10, "b": 6 }, map2 = { "a": 10, "b": 6, "c": 7, "d": 8 };

Flutter:How to merge two objects and sum the values of the same key?

CodePudding user response：

Do forEach on the longest map and check if the small map contains the key if it does then update the value with the sum or add the new.

  map2.forEach((key, value) {
    if (map1.containsKey(key)) {
      map1[key] = value   map1[key]!;
    } else {
      map1[key] = map2[key]!;
    }
  });

map1 will be the final result.

CodePudding user response：

So, if you want to combine/merge the two maps use this code this answer:

final firstMap = {"1":"2"};
final secondMap = {"2":"3"};

final thirdMap = { // here simple adding element to map
...firstMap,
...secondMap,
};

but if you want to make sum and merge use this :

map2.forEach((k, v) {
if (map1.containsKey(k)) { // check if the map has more then 2 values as the 1st one
  map1[k] = v   map1[k]!; // if yes so make the some
} else {
  map1[k] = map2[k]!; // if no then add the values to map
}
});

as MEET Prajapati asnwer.