如何排序地图的值? [英] How to sort map's values?
本文介绍了如何排序地图的值?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
有人可以给我一个提示吗?我想按照列表长度对地图的值进行排序。
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],
"m7": [0, 3, 7, 10],
"6": [0, 4, 7, 9],
"9": [0, 4, 7, 10, 14],
"sus2": [0, 2, 7],
"sus4": [0, 5, 7],
"omit3": [0, 7],
"#5": [0, 4, 8],
"+7b9#11": [0, 4, 8, 10, 13, 18],
"+9": [0, 4, 8, 10, 14]
};
推荐答案
import 'dart:collection';
/// sorts the ListMap (== A Map of List<V>) 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;
}
结果:
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] }
这篇关于如何排序地图的值?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文