javascript - Javascript查找json值

Question

我需要在国家/地区的 json 列表中进行搜索。json就像：

[ 
{"name": "Afghanistan", "code": "AF"}, 
{"name": "Åland Islands", "code": "AX"}, 
{"name": "Albania", "code": "AL"}, 
{"name": "Algeria", "code": "DZ"}
]

我只从数据库中获取代码并输出整个名称。因此，如果我得到“AL”，我想从 json“Albania”中检索

Answer 1

我建议使用 JavaScript 的 Array 方法filter()按值识别元素。它通过使用“测试数组的每个元素的函数来过滤数据。返回 true 以保留元素，否则返回 false ..”

下面的函数过滤数据，返回回调返回的数据true，即 wheredata.code等于请求的国家代码。

function getCountryByCode(code) {
  return data.filter(
      function(data){ return data.code == code }
  );
}

var found = getCountryByCode('DZ');

请看下面的演示：

var data = [{
  "name": "Afghanistan",
  "code": "AF"
}, {
  "name": "Åland Islands",
  "code": "AX"
}, {
  "name": "Albania",
  "code": "AL"
}, {
  "name": "Algeria",
  "code": "DZ"
}];


function getCountryByCode(code) {
  return data.filter(
    function(data) {
      return data.code == code
    }
  );
}

var found = getCountryByCode('DZ');

document.getElementById('output').innerHTML = found[0].name;

<div id="output"></div>

这是一个 JSFiddle。

Answer 2

var obj = [
  {"name": "Afghanistan", "code": "AF"}, 
  {"name": "Åland Islands", "code": "AX"}, 
  {"name": "Albania", "code": "AL"}, 
  {"name": "Algeria", "code": "DZ"}
];

// the code you're looking for
var needle = 'AL';

// iterate over each element in the array
for (var i = 0; i < obj.length; i++){
  // look for the entry with a matching `code` value
  if (obj[i].code == needle){
     // we found it
    // obj[i].name is the matched result
  }
}

Answer 3

只需以函数式的方式使用 ES6find()函数：

var data=[{name:"Afghanistan",code:"AF"},{name:"Åland Islands",code:"AX"},{name:"Albania",code:"AL"},{name:"Algeria",code:"DZ"}];

let country = data.find(el => el.code === "AL");
// => {name: "Albania", code: "AL"}
console.log(country["name"]);

或 Lodash _.find：

var data=[{name:"Afghanistan",code:"AF"},{name:"Åland Islands",code:"AX"},{name:"Albania",code:"AL"},{name:"Algeria",code:"DZ"}];

let country = _.find(data, ["code", "AL"]);
// => {name: "Albania", code: "AL"}
console.log(country["name"]);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>

Answer 4

首先将此结构转换为“字典”对象：

dict = {}
json.forEach(function(x) {
    dict[x.code] = x.name
})

然后简单地

countryName = dict[countryCode]

对于国家列表，这无关紧要，但对于较大的列表，此方法可确保即时查找，而简单搜索将取决于列表大小。

Answer 5

使@showdev答案更笼统。

var getObjectByValue = function (array, key, value) {
    return array.filter(function (object) {
        return object[key] === value;
    });
};

例子：

getObjectByValue(data, "code", "DZ" );