How to convert List to Map or vice-versa in Dart| Flutter By Example

This tutorial shows multiple ways to convert List to Map in Dart or flutter programming.

The List is a dynamic collection of objects in Dart. The map is a data structure to store key and value pairs.

Both are different types in Dart or Flutter, and We have to write a code to convert from one type into another.

How to convert List to Map in Dart or Flutter programming

List.asMap() method converts a list into map type with indexed keys. And the returned map is unmodified and non-editable.

Here is an example program

main() {
  List wordsList = ['one', 'two', 'three'];
  Map wordsMap = wordsList.asMap();
  print(wordsMap); //{0: one, 1: two, 2: three}
  var numberList = [3, 6, 2, 7, 51, 15, 4];
  Map numbersMap = numberList.asMap();// {0: 3, 1: 6, 2: 2, 3: 7, 4: 51, 5: 4}
  print(numbersMap);
}

How to convert Map to List in Dart or Flutter programming?

The map contains keys and values.

to convert to List, use toList() method. map.keys returns keys of type Iterable<dynamic> and map.values returns values of type Iterable<dynamic>. So call toList() method on returned keys and values to convert to List type.

map.keys.toList(): converts keys into List of keys

map.keys.toList(): method converts keys int List of values

Here is an example program to convert map key and values into separate lists

main() {
  List wordsList = ['one', 'two', 'three'];
  Map wordsMap = wordsList.asMap();
  print(wordsMap); //{0: one, 1: two, 2: three}
  
  var keyList = wordsMap.keys.toList();
  print(keyList);
  var valuesList = wordsMap.values.toList();
  print(valuesList);
}

Conclusion

Learn How to Convert List to Map or Map to List in Dart or flutter programming.