blocks|key|223574|text|首先将此结构转换为“字典”对象：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|223575|dict+=+{}
json.forEach(function(x)+{
++++dict[x.code]+=+x.name
})|code-block|syntax|javascript|223576|然后简单地|223577|countryName+=+dict[countryCode]|223578|对于国家/地区列表，这并不重要，但对于较大的列表，此方法可确保即时查找，而简单的搜索将取决于列表大小。|223579|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

<p>First convert this structure to a "dictionary" object:</p>

<pre><code>dict = {}
json.forEach(function(x) {
    dict[x.code] = x.name
})
</code></pre>

<p>and then simply</p>

<pre><code>countryName = dict[countryCode]
</code></pre>

<p>For a list of countries this doesn't matter much, but for larger lists this method guarantees the instant lookup, while the naive searching will depend on the list size.</p>


blocks|key|223586|text|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%2B%2B){
++//+look+for+the+entry+with+a+matching+`code`+value
++if+(obj[i].code+==+needle){
+++++//+we+found+it
++++//+obj[i].name+is+the+matched+result
++}
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|223587|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>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 &lt; 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
  }
}
</code></pre>


blocks|key|7079|text|我建议使用JavaScript的数组方法filter()通过值来标识元素。它通过使用“函数来测试数组的每个元素。返回true以保留元素，否则返回false”来过滤数据。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|7080|下面的函数过滤数据，返回回调返回true的数据，即data.code等于请求的国家代码。|7081|function+getCountryByCode(code)+{
++return+data.filter(
++++++function(data){+return+data.code+==+code+}
++);
}

var+found+=+getCountryByCode('DZ');|code-block|syntax|javascript|7082|请看下面的演示：|7083|​|7084|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;|7085|<div+id="output"></div>|7086|7087|Here's+a+JSFiddle。|7088|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter|1|http://jsfiddle.net/KMQ7c/1/^0|K|8|K|8|0|0|G|4|P|9|0|0|0|0|0|0|0|0|H|1|0^^$0|@$1|2|3|4|5|6|7|17|8|@$9|18|A|19|B|C]]|D|@$9|1A|A|1B|1|1C]]|E|$]]|$1|F|3|G|5|6|7|1D|8|@$9|1E|A|1F|B|C]|$9|1G|A|1H|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|1I|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|1J|8|@]|D|@]|E|$]]|$1|O|3|P|5|6|7|1K|8|@]|D|@]|E|$]]|$1|Q|3|R|5|J|7|1L|8|@]|D|@]|E|$K|L]]|$1|S|3|T|5|J|7|1M|8|@]|D|@]|E|$K|L]]|$1|U|3|P|5|6|7|1N|8|@]|D|@]|E|$]]|$1|V|3|W|5|6|7|1O|8|@]|D|@$9|1P|A|1Q|1|1R]]|E|$]]|$1|X|3|-4|5|6|7|1S|8|@]|D|@]|E|$]]]|Y|$Z|$5|10|11|12|E|$13|14]]|15|$5|10|11|12|E|$13|16]]]]

<p>I suggest using JavaScript's Array method <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter" rel="noreferrer"><code>filter()</code></a> to identify an element by value. It filters data by using a "function to test each element of the array. Return true to keep the element, false otherwise.."</p>

<p>The following function filters the data, returning data for which the callback returns <code>true</code>, i.e. where <code>data.code</code> equals the requested country code.</p>



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

var found = getCountryByCode('DZ');
</code></pre>

<p>See the demonstration below:</p>

<p><div class="snippet" data-lang="js" data-hide="true" data-console="false" data-babel="false">
<div class="snippet-code snippet-currently-hidden">
<pre class="snippet-code-js lang-js prettyprint-override"><code>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;</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div id="output"&gt;&lt;/div&gt;</code></pre>
</div>
</div>
</p>

<p><a href="http://jsfiddle.net/KMQ7c/1/" rel="noreferrer">Here's a JSFiddle</a>.</p>


blocks|key|223654|text|使@showdev的答案更具一般性。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|223655|var+getObjectByValue+=+function+(array,+key,+value)+{
++++return+array.filter(function+(object)+{
++++++++return+object[key]+===+value;
++++});
};|code-block|syntax|javascript|223656|示例：|223657|getObjectByValue(data,+"code",+"DZ"+);|223658|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/19254067/6904888^0|1|8|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

<p>Making more general the <a href="https://stackoverflow.com/a/19254067/6904888">@showdev</a> answer.</p>
<pre><code>var getObjectByValue = function (array, key, value) {
    return array.filter(function (object) {
        return object[key] === value;
    });
};
</code></pre>
<p>Example:</p>
<pre><code>getObjectByValue(data, &quot;code&quot;, &quot;DZ&quot; );
</code></pre>


<p>I need to search inside a json list of countries. The json is like:</p>

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

<p>I get from database only the code and would output the entire name. So if I get "AL" I would like to retrieve from json "Albania"</p>


Javascript find json value

数据库

我需要在json国家列表中进行搜索。json类似于：[ {"name": "Afghanistan", "code": "AF"}, {"name": "Åland Islands", "code": "AX"}, {"name": "Albania", "code": "AL"}, {"name": "Algeria...

问Javascript查找json值
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