How to sort map's values?

Question

Can someone give me a hint? I want to sort a map\'s values by the length of the lists.

var chordtypes = {
  \"maj\": [0, 4, 7],
  \"M7\": [0, 4, 7, 11],
  \"         


        

Answer 1

A function that does sort a Map of List on their length.

import 'dart:collection';

/// sorts the ListMap (== A Map of List) on the length
/// of the List values.
LinkedHashMap sortListMap(LinkedHashMap map) {
    List mapKeys = map.keys.toList(growable : false);
    mapKeys.sort((k1, k2) => map[k1].length - map[k2].length);
    LinkedHashMap resMap = new LinkedHashMap();
    mapKeys.forEach((k1) { resMap[k1] = map[k1] ; }) ;        
    return resMap;
}

result for :

var res = sortListMap(chordtypes);
print(res);

==>

{ omit3: [0, 7], 
  maj: [0, 4, 7], 
  sus2: [0, 2, 7], 
  sus4: [0, 5, 7], 
  #5: [0, 4, 8], 
  M7: [0, 4, 7, 11], 
  m7: [0, 3, 7, 10], 
  6: [0, 4, 7, 9], 
  9: [0, 4, 7, 10, 14], 
  +9: [0, 4, 8, 10, 14], 
  +7b9#11: [0, 4, 8, 10, 13, 18] }