解析数据列表

下面的这个数据
list下面有四个数组
每组数组是个{}
每组下面都有个pictureUrl和tagGroups
tagGroups下面又有一堆数组
每组数据下面又是一堆{}
现在的显示方法是把每个pictureUrl都显示出来
然后在给他对应的traGroups下面的tagName显示到pictureUrl上
这样要怎么对应

{
    "success": true,
    "msg": "操作成功",
    "data": {
        "list": [
            {
                "pictureUrl": "/201604/45A343F8D754468E8963FE02624A7177.jpeg",
                "tagGroups": [
                    [{"tagName": "滋养修护"},{"tagName": "ElizabethArden/雅顿"}],
                    [{"tagName": "美白"}]
                ]
            },
            {
                "pictureUrl": "/201604/45A343F8D754468E8963FE02624A7177.jpeg",
                "tagGroups": [
                    [{"tagName": "ElizabethArden/雅顿"}],
                    [{"tagName": "美白"}]
                ]
            },
            {
                "pictureUrl": "/201604/FCB3B6D6DFC0462689CD975BDF518024.jpeg",
                "tagGroups": [
                    [{"tagName": "SULWHASOO/雪花秀"}],
                    [{"tagName": "补水"}],]
                ]
            },
            {
                "pictureUrl": "/201604/F871063AF6004712B2FB6762790F39A4.jpeg",
                "tagGroups": [
                    [{"tagName": "Estee Lauder/雅诗兰黛"},{"tagName": "修护"},{"tagName": "保湿抗皱"}]
                ]
            }
        ]
    }
}

---

var data = {"success":true,"msg":"操作成功","data":{"list":[{"id":164276,"status":0,"createTime":1460689162000,"updateTime":1460689162000,"postId":6970541,"location":0,"pictureUrl":"/201604/92F92BD4E5EC4D30826BB23246D83E8C.jpeg","description":"","cover":false,"height":640,"width":640,"pictureType":"NORMAL","align":"CENTER","emoji":false,"hanldeSql":false,"tagGroups":[[{"ratio":"0.503125,0.700000","tagName":"滋养修护","pid":217,"pv":932008412522,"type":"effect","tagId":971,"vid":509290}],[{"ratio":"0.448438,0.782812","tagName":"美白","pid":217,"pv":932007903239,"type":"effect","tagId":2824,"vid":7}],[{"ratio":"0.476562,0.667188","tagName":"ElizabethArden/雅顿","pid":9,"pv":0,"type":"brand","tagId":6627,"vid":0}]]},{"id":164277,"status":0,"createTime":1460689162000,"updateTime":1460689162000,"postId":6970541,"location":1,"pictureUrl":"/201604/45A343F8D754468E8963FE02624A7177.jpeg","description":"","cover":false,"height":640,"width":640,"pictureType":"NORMAL","align":"CENTER","emoji":false,"hanldeSql":false,"tagGroups":[[{"ratio":"0.634375,0.603125","tagName":"ElizabethArden/雅顿","pid":9,"pv":0,"type":"brand","tagId":6627,"vid":0},{"ratio":"0.634375,0.603125","tagName":"美白","pid":217,"pv":932007903239,"type":"effect","tagId":2824,"vid":7}]]},{"id":164278,"status":0,"createTime":1460689162000,"updateTime":1460689162000,"postId":6970541,"location":2,"pictureUrl":"/201604/FCB3B6D6DFC0462689CD975BDF518024.jpeg","description":"","cover":false,"height":640,"width":640,"pictureType":"NORMAL","align":"CENTER","emoji":false,"hanldeSql":false,"tagGroups":[[{"ratio":"0.614062,0.648438","tagName":"SULWHASOO/雪花秀","pid":9,"pv":38654715828,"type":"brand","tagId":219,"vid":10164},{"ratio":"0.614062,0.648438","tagName":"补水","pid":217,"pv":932007903244,"type":"effect","tagId":1693,"vid":12}]]},{"id":164279,"status":0,"createTime":1460689162000,"updateTime":1460689162000,"postId":6970541,"location":3,"pictureUrl":"/201604/F871063AF6004712B2FB6762790F39A4.jpeg","description":"","cover":false,"height":640,"width":640,"pictureType":"NORMAL","align":"CENTER","emoji":false,"hanldeSql":false,"tagGroups":[[{"ratio":"0.595312,0.584375","tagName":"Estee Lauder/雅诗兰黛","pid":9,"pv":38654715671,"type":"brand","tagId":184,"vid":10007},{"ratio":"0.595312,0.584375","tagName":"修护","pid":217,"pv":932007903246,"type":"effect","tagId":1994,"vid":14},{"ratio":"0.595312,0.584375","tagName":"保湿抗皱","pid":217,"pv":932008411484,"type":"effect","tagId":1068,"vid":508252}]]}]}};
var list = data['data']['list'],
    urlTagMap = {};
for(var k in list) {
    var picUrl = list[k]['pictureUrl'];
    urlTagMap[picUrl] = urlTagMap.hasOwnProperty(picUrl) ? urlTagMap[picUrl] : [];
    list[k]['tagGroups'].forEach(function(tagList) {
        tagList.forEach(function(tag) {
            urlTagMap[picUrl].push(tag['tagName']);
        });
    });
}
console.log(urlTagMap);

---

for in 遍历对象 用 . 操作对象属性