CODEWITHSUNDEEP
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Karel Debedts
Karel Debedts

Reputation: 5768

Dart: convert a map to 2 lists

I'm trying to convert the following map into 2 lists.

Map map = {'Jack': 'red', 'Adam': 'blue', 'Katherin': 'green'};

I would like to become this: (the order is important)

List myList1 = ['Jack', 'Adam', 'Katherin'];
List myList2 = ['red', 'blue', 'green'];

Is this possible and how can it be done? I searched trough stack overflow and the responses gave me this list (what's not what I'm searching for)

[{ Jack, 'red' }, { Adam, 'blue' }, { Katherin, 'green' }] // not what I need

Thanks for the help and effort!

Upvotes: 1

Views: 1700

Answers (3)

Amir Hoseinian
Amir Hoseinian

Reputation: 2352

If I get the question right, what you are looking for is already build into Map Class. take a look:

Map map = {'Jack': 'red', 'Adam': 'blue', 'Katherin': 'green'};

print(map.keys.toList());
print(map.values.toList());

Output:

[Jack, Adam, Katherin]
[red, blue, green]

I hope it is what you are looking for.

Upvotes: 2

Bret Hagen
Bret Hagen

Reputation: 123

Simply fill your map and use the keys and values iterable getters to form a list.

void main() {
  Map<String, String> map = Map<String, String>();
  map["Jack"] = "red";
  map["Adam"] = "blue";
  map["Katherin"] = "green";
  print(map.toString());

  List<String> names = map.keys.toList();
  List<String> colors = map.values.toList();
  print(names);
  print(colors);
}

Output

{Jack: red, Adam: blue, Katherin: green}
[Jack, Adam, Katherin]
[red, blue, green]

Upvotes: 1

Peter Haddad
Peter Haddad

Reputation: 80904

To be able to do that you can do the following:

Map map = {'Jack': 'red', 'Adam': 'blue', 'Katherin': 'green'};

List<String> values = List();  
List<String> keys   = List();

map.forEach((k,v) => values.add(v));
print(values);

map.forEach((k,v) => keys.add(k));
print(keys);

Use forEach to iterate inside the values of the map, then use the add() method to add the key to one list and the values to another list.

Upvotes: 1

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