如何通过遍历JSON查找所需的数据

Question

我对vue js完全陌生，我只想遍历json数据，并想找出我所需的数据是否在文件中可用。这是json的示例：

[
{
    "id": "text-5",
    "widget": "hello",
    "params": {
        "0": "section-right",
        "name": "Right",
        "id": "section",
        "description": "",
        "class": "",
        "after_title": "",
        "widget_id": "text-5"
    },
    "instance": {
        "title": "St",
        "text": "",
        "filter": false,
        "sidebar": "se-right",
        "sidebar-order": 0,
        "inherited": "yes",
        "number": 0
    }
},
{
    "id": "text-5",
    "widget": "hello",
    "params": {
        "0": "section-right",
        "name": "Right",
        "id": "section",
        "description": "",
        "class": "",
        "after_title": "",
        "widget_id": "text-5"
    },
    "instance": {
        "title": "Twitter Feed",
        "twitteruser": "Stei",
        "sidebar": "sectht",
        "sidebar-order": "4"
    }
}]

我只想遍历并查找"instance“是否包含值twitteruser。

我试过这段代码：

const data = JSON.parse(res).data
console.log(data[0].instance)

Answer 1

您可以使用以下方式进行迭代。

    <script>
    var json_data = [
    {
        "id": "text-5",
        "widget": "hello",
        "params": {
            "0": "section-right",
            "name": "Right",
            "id": "section",
            "description": "",
            "class": "",
            "after_title": "",
            "widget_id": "text-5"
        },
        "instance": {
            "title": "St",
            "text": "",
            "filter": false,
            "sidebar": "se-right",
            "sidebar-order": 0,
            "inherited": "yes",
            "number": 0
        }
    },
    {
        "id": "text-5",
        "widget": "hello",
        "params": {
            "0": "section-right",
            "name": "Right",
            "id": "section",
            "description": "",
            "class": "",
            "after_title": "",
            "widget_id": "text-5"
        },
        "instance": {
            "title": "Twitter Feed",
            "twitteruser": "Stei",
            "sidebar": "sectht",
            "sidebar-order": "4"
        }
    }];


    for( var i = 0; i < json_data.length; i++) {

        if(typeof json_data[i].instance == 'object' && typeof json_data[i].instance.twitteruser != 'undefined'){
            console.log(json_data[i].instance.twitteruser);
        }

    }

    </script>

Answer 2

如果你的data是一个从你的JSON解析的数组，你可以这样做：

var filtered = data.filter(function(item) {
   return item.instance && item.instance.twitteruser  
})

filtered将是一个仅包含具有twitteruser的元素的新数组

如果您只想知道是否存在，可以测试filtered的长度

if (filtered.length > 0) {
   // do something
}

Answer 3

如果我没理解错的话，您有一个对象数组，每个对象都包含instance键下的另一个对象，并且您希望了解这些instance对象中是否有包含键twitteruser的对象。只需编写一个for循环并检查：

​

const data = [{
    "id": "text-5",
    "widget": "hello",
    "params": {
      "0": "section-right",
      "name": "Right",
      "id": "section",
      "description": "",
      "class": "",
      "after_title": "",
      "widget_id": "text-5"
    },
    "instance": {
      "title": "St",
      "text": "",
      "filter": false,
      "sidebar": "se-right",
      "sidebar-order": 0,
      "inherited": "yes",
      "number": 0
    }
  },
  {
    "id": "text-5",
    "widget": "hello",
    "params": {
      "0": "section-right",
      "name": "Right",
      "id": "section",
      "description": "",
      "class": "",
      "after_title": "",
      "widget_id": "text-5"
    },
    "instance": {
      "title": "Twitter Feed",
      "twitteruser": "Stei",
      "sidebar": "sectht",
      "sidebar-order": "4"
    }
  }
];

for (var i = 0; i < data.length; i++) {
  if (data[i].instance.twitteruser !== undefined) {
    console.log("Found it at index " + i + ".");
    break;
  }
}

​