I have 2 maps and I want to get the missing elements as a list. For example:

var map1= [
   {"name":"name1","email":"[email protected]"},
   {"name":"name2","email":"[email protected]"},
   {"name":"name3","email":"[email protected]"},
 ];
   var map2= [
   {"name":"name1","email":"[email protected]"},
   {"name":"name2","email":"[email protected]"},
  
 ];

Output: [{"name":"name3","email":"[email protected]"}]

I tried this approach:

var removedElements = map2.where((element) => 
                                      !map1
                                          .contains(element['email']))
                                      .toList();

but it doesn't work. Any help would be great.

CodePudding user response：

try with this

void main() {
  var map1 = [
    {"name": "name1", "email": "[email protected]"},
    {"name": "name2", "email": "[email protected]"},
    {"name": "name3", "email": "[email protected]"},
  ];
  var map2 = [
    {"name": "name1", "email": "[email protected]"},
    {"name": "name2", "email": "[email protected]"},
  ];

  var removedElements = [];
  var k;
  for (var i in map2) {
    for (var j in map1) {
      if (i["email"] != j["email"]) {
        k = j;
      }
    }
     removedElements.add(k);
  }

  print(removedElements.toSet().toList());
}

Another approach

 var removedElements =
      map2.where((element) {
       for(var i in map1){
         if(i["email"] == element["email"]){
           return false;
         } else{
           return true;
         }
       }
      }).toList();

  print(removedElements);

output : [{name: name3, email: [email protected]}]