解析包含数组数组的 json 给出“未定义”

Question

我正在尝试以 JSON 格式访问数组的数组中的元素，但我收到了undefined。

错误 - 未捕获的类型错误：无法读取第 1 行未定义的属性“lsi_short_name”。 9 $("#jsondata").append(

代码如下：

var data = '{"response":[[{"1":{"type":"p","lsi_short_name":"A","entities":["term_Quantity"]}}, {"2":{"type":"p","lsi_short_name":"B","entities":["term_Quantity"]}}, {"4":{"type":"d","lsi_short_name":"D","entities":["term_Quantity"]}}, {"5":{"type":"p","lsi_short_name":"E","entities":["term_Quantity"]}}], [{"1":{"type":"p","lsi_short_name":"A","entities":["term_Quantity"]}}, {"2":{"type":"p","lsi_short_name":"B","entities":["term_Quantity"]}}, {"4":{"type":"d","lsi_short_name":"D","entities":["term_Quantity"]}}, {"6":{"type":"p","lsi_short_name":"F","entities":["term_Quantity"]}}]]}';
var obj = JSON.parse(data);

for(i=0;i<obj.response.length;i++) {
    for (j=0; j < obj.response[i].length; j++) {
        $("#jsondata").append("<li onclick=jsonDetails('"+obj.response[i][j][j+1]['lsi_short_name'] +"','"+ obj.response[i][j][j+1]['entities']+"','"+ obj.response[i][j][j+1]['attributes']+"')>"+obj.response[i][j][j+1]['lsi_short_name']+"</li>");  
    }
    $("#jsondata").append("<br>");
}

提前致谢。

Answer 1

您的密钥顺序不是串行的，这就是为什么您不应该使用j+1。因此，您可以先使用Object.keys() 获取确切的密钥，然后访问属性：示例：

var data = '{"response":[[{"1":{"type":"p","lsi_short_name":"A","entities":["term_Quantity"]}}, {"2":{"type":"p","lsi_short_name":"B","entities":["term_Quantity"]}}, {"4":{"type":"d","lsi_short_name":"D","entities":["term_Quantity"]}}, {"5":{"type":"p","lsi_short_name":"E","entities":["term_Quantity"]}}], [{"1":{"type":"p","lsi_short_name":"A","entities":["term_Quantity"]}}, {"2":{"type":"p","lsi_short_name":"B","entities":["term_Quantity"]}}, {"4":{"type":"d","lsi_short_name":"D","entities":["term_Quantity"]}}, {"6":{"type":"p","lsi_short_name":"F","entities":["term_Quantity"]}}]]}';
//var data = '{"response": "[[{"1": {"attributes": [], "entities": [], "lsi_short_name": "a", "type": "process"}}, {"2": {"attributes": ["d"], "entities": ["c"], "lsi_short_name": "b", "type": "process"}}], [{"1": {"attributes": [], "entities": [], "lsi_short_name": "a", "type": "process"}},{"6": {"attributes": [], "entities": [], "lsi_short_name": "f", "type": "process"}}]]"}';

var obj = JSON.parse(data);
for(var i = 0; i < obj.response.length; i++) {
    for (var j = 0; j < obj.response[i].length; j++) {
        var key = Object.keys(obj.response[i][j])[0];
        $("#jsondata").append("<li onclick=jsonDetails('" + obj.response[i][j][key]['lsi_short_name'] +"','"+ obj.response[i][j][key]['entities']+"','"+ obj.response[i][j][key]['attributes']+"')>"+obj.response[i][j][key]['lsi_short_name']+"</li>");
    }
    $("#jsondata").append("<br>");
}

Answer 2

您正试图访问超出数组长度的对象。您也没有任何名为 attributes 的属性。

你可以先从对象中获取值，然后像下面这样使用索引：

var data = '{"response":[[{"1":{"type":"p","lsi_short_name":"A","entities":["term_Quantity"]}}, {"2":{"type":"p","lsi_short_name":"B","entities":["term_Quantity"]}}, {"4":{"type":"d","lsi_short_name":"D","entities":["term_Quantity"]}}, {"5":{"type":"p","lsi_short_name":"E","entities":["term_Quantity"]}}], [{"1":{"type":"p","lsi_short_name":"A","entities":["term_Quantity"]}}, {"2":{"type":"p","lsi_short_name":"B","entities":["term_Quantity"]}}, {"4":{"type":"d","lsi_short_name":"D","entities":["term_Quantity"]}}, {"6":{"type":"p","lsi_short_name":"F","entities":["term_Quantity"]}}]]}';

var obj = JSON.parse(data);
for(let i=0;i<obj.response.length;i++){  
  for (let j=0; j < obj.response[i].length; j++) {
  let o = Object.values(obj.response[i][j])[0];
  $("#jsondata").append("<li onclick=jsonDetails('"+o['lsi_short_name'] +"','"+ o['entities'][0]+"')>"+o['lsi_short_name']+"</li>");
  }
  $("#jsondata").append("<br>");
}

function jsonDetails(sn, en){
  console.log(sn + '::' + en)
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div id="jsondata"></div>

Answer 3

您的 for 循环应如下所示：

var obj = JSON.parse(data);
for(i=0;i<obj.response.length;i++){
    var x = obj.response[i];
    for (j=0; j < x.length; j++) {    
       //Assuming the keys are serial else you need to get all the keys using Object.keys method.
       var keyName = (j+1).toString();
       //Access various prop of your json like this -->    x[j][keyName]["lsi_short_name"]
    }
}