js字典的操作

1. 字典的遍历

var dic={
    
    "a": "AA", "b": "BB", "c":"CC"} //不能length去for循环(length:undefined)

dic["D"]="DD"; //新增键值对
var tmp=dic["D"]; //通过key获取值

for (var key in dic) {
    
    
　　var item = dic[key];
　　console.log(item); //AA,BB,CC,DD
}

# 下拉框
for(var key in datas){
    
    
    html += '<option value="'+key+'">'+datas[key]+'</option>';
}

2. 字典排序

2.1 字典元素按key值排序

var dic = {
    
    
	"abc": "a",
	"aac": "b",
	"bbc": "c",
	"aab": "d",
}

console.log("字典元素按key值排序: ");
var res = Object.keys(dic).sort(); 
for(var key in res){
    
    
       console.log("key: " + res[key] + " ,value: " + dic[res[key]]["score"]);
}

2.2 字典元素按value值排序

var dic = {
    
    
	2: {
    
    "score": 20},
	1: {
    
    "score": 25},
	3: {
    
    "score": 15},
	4: {
    
    "score": 60},
}

console.log("字典元素按value值排序: ");
var res2 = Object.keys(dic).sort(function(a,b){
    
     return dic[a]["score"]-dic[b]["score"];             });
for(var key in res2){
    
    
	console.log("key: " + res2[key] + " ,value: " + dic[res2[key]]["score"]);
}