Question

js中json数据获取重复数据的次数

例如：var a = [{"id":1,"name":"name1"},{"id":2,"name":"name2"},{"id":1,"name":"name1"}];
想要的结果为（只需要判断id）：id为1的次数为2,id为2的次数为1
大神们，速度啊，在线等

Answer 1

var a = [{"id":1,"name":"name1"},{"id":2,"name":"name2"},{"id":1,"name":"name1"}];

function countId(data){
var count={};
for(var i=0;i<data.length;i++){
if(count[data[i].id]){
count[data[i].id]++;;
continue;
}
count[data[i].id]=1;
}
return count;
}
var result= countId(a);
//循环获取 用这个
for(var i in result){

console.log("id为"+i+"的统计结果为"+result[i]);
}

代码扔进控制台执行。

Answer 2

var a = [{"id":1,"name":"name1"},{"id":2,"name":"name2"},{"id":1,"name":"name1"}];
var b;
b = new Object();
var i;
for (i=0; i<a.length; i++)
{
    var id = a[i]["id"];
    if(b[id] == undefined)
        b[id] = 1;
    else
        b[id] += 1;   
}
for(e in b)
    alert(e.toString() + ":" + b[e]);

Answer 3

var a = [{"id":1,"name":"name1"},{"id":2,"name":"name2"},{"id":1,"name":"name1"},{"id":1,"name":"name1"},{"id":2,"name":"name2"},{"id":1,"name":"name1"}];
var idTimes1=0;var idTimes2=0;
for(var i in a){
if(a[i].id==1) idTimes1++;
if(a[i].id==2)idTimes2++;
}
alert(idTimes1+"="+idTimes2);

追问

你这个感觉不太好，因为我id不止1和2，所以还要去声明更多变量