Merge value of map and insert it into another map-CodePudding

I have a Map <String,List> map1 that looks like that

{First: ['1', '2', '3', '4'], Second: ['A', 'B']}

I want to create another Map<String,Map<String,int>> as a ruslt of values from map1 to be like that

{'1A' : ['String1':10,'String2':20], '1B' : ['String1':10,'String2':20] , '2A' : ['String1':10,'String2':20], '2B' : ['String1':10,'String2':20], '3A' : ['String1':10,'String2':20] , '3C' : ['String1':10,'String2':20]}

I hope you get my point

CodePudding user response：

Similar question Generate all combinations from multiple lists
Reference Source: https://stackoverflow.com/a/17193002/6576315

void main() async{
  
  Map<String,List> rawMapList = {"First": ['1', '2', '3', '4'], "Second": ['A', 'B']};
  List<Map<String, int>> mapResult = [{"String1" : 10}, {"String2" : 20}];
  List<String> keyList = <String>[];
  
      
  generatePermutations(rawMapList.values.toList(), keyList, 0, "");
  
  var result = Map.fromEntries(keyList.map((value) => MapEntry(value, mapResult)));
  
  print(result);
  
}


void generatePermutations(List<List<dynamic>> lists, List<String> result, int depth, String current) {
    if (depth == lists.length) {
        result.add(current);
        return;
    }

    for (int i = 0; i < lists.elementAt(depth).length; i  ) {
        generatePermutations(lists, result, depth   1, current   lists.elementAt(depth).elementAt(i));
    }
}

Try first on DartPad, This code block will print

{1A: [{String1: 10}, {String2: 20}], 1B: [{String1: 10}, {String2: 20}], 2A: [{String1: 10}, {String2: 20}], 2B: [{String1: 10}, {String2: 20}], 3A: [{String1: 10}, {String2: 20}], 3B: [{String1: 10}, {String2: 20}], 4A: [{String1: 10}, {String2: 20}], 4B: [{String1: 10}, {String2: 20}]}

Do upvote reference

CodePudding user response：

the solution

Map<String, dynamic> data = {
    'First': ['1', '2', '3', '4'],
    'Second': ['A', 'B']
  };
Map<String, dynamic> ans = {};
  
  calculate() {
    for (var i in (data['First'] as List<dynamic>)) {
      for (var j in (data['Second'] as List<dynamic>)) {
        ans.addAll({
          "$i$j": [
            {'String1': 10},
            {'String2': 20}
          ],
        });
      }
    }
    log("$ans");
  }