blocks|key|1286550|text|如果我没理解错的话：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1286551|var+hash+=+{};
hash['bob']+=+123;
hash['joe']+=+456;

var+sum+=+0;
for+(var+name+in+hash)+{
++++sum+%2B=+hash[name];
}
alert(sum);+//+579|code-block|syntax|javascript|1286552|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

If I understood you correctly:

<pre><code>var hash = {};
hash['bob'] = 123;
hash['joe'] = 456;

var sum = 0;
for (var name in hash) {
 sum += hash[name];
}
alert(sum); // 579
</code></pre>

blocks|key|1286612|text|在javascript中，键值数组被存储为对象。在javascript中有数组这样的东西，但它们在某种程度上仍然被认为是对象，请检查这个家伙的答案-+Why+can+I+add+named+properties+to+an+array+as+if+it+were+an+object?|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1286613|数组通常使用方括号语法，对象("key=>value“数组)使用花括号语法，尽管您可以使用方括号语法访问和设置对象属性，如Alexey+Romanov所示。|1286614|javascript中的数组通常只与数字的、自动递增的键一起使用，但是javascript对象可以保存命名的键值对、函数甚至其他对象。|1286615|简单数组，例如。|1286616|$(document).ready(function(){

++++var+countries+=+['Canada','Us','France','Italy'];
++++console.log('I+am+from+'%2Bcountries[0]);
++++$.each(countries,+function(key,+value)+{
++++++++console.log(key,+value);
++++});

});|code-block|syntax|javascript|1286617|输出-|1286618|0“加拿大”|1286619|1“我们”|1286620|2“法国”|1286621|3“意大利”|1286622|我们在上面看到，我们可以使用jQuery.each函数循环一个数字数组，并使用带有数字键的方括号在循环外部访问信息。|1286623|简单对象(json)|1286624|$(document).ready(function(){

++++var+person+=+{
++++++++name:+"James",
++++++++occupation:+"programmer",
++++++++height:+{
++++++++++++feet:+6,
++++++++++++inches:+1
++++++++},
++++}

++++console.log("My+name+is+"%2Bperson.name%2B"+and+I+am+a+"%2Bperson.height.feet%2B"+ft+"%2Bperson.height.inches%2B"+"%2Bperson.occupation);

++++$.each(person,+function(key,+value)+{
++++++++console.log(key,+value);
++++});

});|1286625|1286626|我叫詹姆斯，身高6英尺1英寸的程序员|1286627|姓名:詹姆斯|1286628|职业程序员|1286629|高度对象{英尺:+6，英寸:+1}|1286630|在php这样的语言中，这将被认为是具有键值对的多维数组，或者是数组中的数组。我假设，因为您询问了如何遍历键值数组，所以您可能想知道如何获得像上面的person对象这样的对象(key=>value数组)来拥有多个person。|1286631|好吧，既然我们知道javascript数组通常用于数字索引，而对象更灵活地用于关联索引，我们将一起使用它们来创建一个可以循环的对象数组，如下所示-|1286632|JSON数组(对象数组)-|1286633|$(document).ready(function(){

++++var+people+=+[
++++++++{
++++++++++++name:+"James",
++++++++++++occupation:+"programmer",
++++++++++++height:+{
++++++++++++++++feet:+6,
++++++++++++++++inches:+1
++++++++++++}
++++++++},+{
++++++++++++name:+"Peter",
++++++++++++occupation:+"designer",
++++++++++++height:+{
++++++++++++++++feet:+4,
++++++++++++++++inches:+10
++++++++++++}
++++++++},+{
++++++++++++name:+"Joshua",
++++++++++++occupation:+"CEO",
++++++++++++height:+{
++++++++++++++++feet:+5,
++++++++++++++++inches:+11
++++++++++++}
++++++++}
++++];

++++console.log("My+name+is+"%2Bpeople[2].name%2B"+and+I+am+a+"%2Bpeople[2].height.feet%2B"+ft+"%2Bpeople[2].height.inches%2B"+"%2Bpeople[2].occupation%2B"\n");

++++$.each(people,+function(key,+person)+{
++++++++console.log("My+name+is+"%2Bperson.name%2B"+and+I+am+a+"%2Bperson.height.feet%2B"+ft+"%2Bperson.height.inches%2B"+"%2Bperson.occupation%2B"\n");
++++});

});|1286634|1286635|我的名字是Joshua，我是一个5英尺11英寸的CEO|1286636|1286637|我叫彼得，我是一个4英尺10英寸的设计师。|1286638|1286639|注意，在循环外部，我必须使用带有数字键的方括号语法，因为这现在是一个数字索引的对象数组，当然在循环内部，数字键是隐含的。|1286640|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/874205/what-is-the-difference-between-an-array-and-an-object#answer-874237^0|23|1V|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|22|8|@]|9|@$A|23|B|24|1|25]]|C|$]]|$1|D|3|E|5|6|7|26|8|@]|9|@]|C|$]]|$1|F|3|G|5|6|7|27|8|@]|9|@]|C|$]]|$1|H|3|I|5|6|7|28|8|@]|9|@]|C|$]]|$1|J|3|K|5|L|7|29|8|@]|9|@]|C|$M|N]]|$1|O|3|P|5|6|7|2A|8|@]|9|@]|C|$]]|$1|Q|3|R|5|6|7|2B|8|@]|9|@]|C|$]]|$1|S|3|T|5|6|7|2C|8|@]|9|@]|C|$]]|$1|U|3|V|5|6|7|2D|8|@]|9|@]|C|$]]|$1|W|3|X|5|6|7|2E|8|@]|9|@]|C|$]]|$1|Y|3|Z|5|6|7|2F|8|@]|9|@]|C|$]]|$1|10|3|11|5|6|7|2G|8|@]|9|@]|C|$]]|$1|12|3|13|5|L|7|2H|8|@]|9|@]|C|$M|N]]|$1|14|3|P|5|6|7|2I|8|@]|9|@]|C|$]]|$1|15|3|16|5|6|7|2J|8|@]|9|@]|C|$]]|$1|17|3|18|5|6|7|2K|8|@]|9|@]|C|$]]|$1|19|3|1A|5|6|7|2L|8|@]|9|@]|C|$]]|$1|1B|3|1C|5|6|7|2M|8|@]|9|@]|C|$]]|$1|1D|3|1E|5|6|7|2N|8|@]|9|@]|C|$]]|$1|1F|3|1G|5|6|7|2O|8|@]|9|@]|C|$]]|$1|1H|3|1I|5|6|7|2P|8|@]|9|@]|C|$]]|$1|1J|3|1K|5|L|7|2Q|8|@]|9|@]|C|$M|N]]|$1|1L|3|P|5|6|7|2R|8|@]|9|@]|C|$]]|$1|1M|3|1N|5|6|7|2S|8|@]|9|@]|C|$]]|$1|1O|3|16|5|6|7|2T|8|@]|9|@]|C|$]]|$1|1P|3|1Q|5|6|7|2U|8|@]|9|@]|C|$]]|$1|1R|3|1N|5|6|7|2V|8|@]|9|@]|C|$]]|$1|1S|3|1T|5|6|7|2W|8|@]|9|@]|C|$]]|$1|1U|3|-4|5|6|7|2X|8|@]|9|@]|C|$]]]|1V|$1W|$5|1X|1Y|1Z|C|$20|21]]]]

In javascript a key value array is stored as an object. There are such things as arrays in javascript, but they are also somewhat considered objects still, check this guys answer - <a href="https://stackoverflow.com/questions/874205/what-is-the-difference-between-an-array-and-an-object#answer-874237">Why can I add named properties to an array as if it were an object?</a>

Arrays are typically seen using square bracket syntax, and objects ("key=>value" arrays) using curly bracket syntax, though you can access and set object properties using square bracket syntax as Alexey Romanov has shown.

Arrays in javascript are typically used only with numeric, auto incremented keys, but javascript objects can hold named key value pairs, functions and even other objects as well.

Simple Array eg.

<pre><code>$(document).ready(function(){

 var countries = ['Canada','Us','France','Italy'];
 console.log('I am from '+countries[0]);
 $.each(countries, function(key, value) {
 console.log(key, value);
 });

});
</code></pre>

Output -

0 "Canada"

1 "Us"

2 "France"

3 "Italy"

We see above that we can loop a numerical array using the jQuery.each function and access info outside of the loop using square brackets with numerical keys.

Simple Object (json)

<pre><code>$(document).ready(function(){

 var person = {
 name: "James",
 occupation: "programmer",
 height: {
 feet: 6,
 inches: 1
 },
 }

 console.log("My name is "+person.name+" and I am a "+person.height.feet+" ft "+person.height.inches+" "+person.occupation);

 $.each(person, function(key, value) {
 console.log(key, value);
 });

});
</code></pre>

Output -

My name is James and I am a 6 ft 1 programmer

name James

occupation programmer

height Object {feet: 6, inches: 1}

In a language like php this would be considered a multidimensional array with key value pairs, or an array within an array. I'm assuming because you asked about how to loop through a key value array you would want to know how to get an object (key=>value array) like the person object above to have, let's say, more than one person.

Well, now that we know javascript arrays are used typically for numeric indexing and objects more flexibly for associative indexing, we will use them together to create an array of objects that we can loop through, like so -

JSON array (array of objects) -

<pre><code>$(document).ready(function(){

 var people = [
 {
 name: "James",
 occupation: "programmer",
 height: {
 feet: 6,
 inches: 1
 }
 }, {
 name: "Peter",
 occupation: "designer",
 height: {
 feet: 4,
 inches: 10
 }
 }, {
 name: "Joshua",
 occupation: "CEO",
 height: {
 feet: 5,
 inches: 11
 }
 }
 ];

 console.log("My name is "+people[2].name+" and I am a "+people[2].height.feet+" ft "+people[2].height.inches+" "+people[2].occupation+"\n");

 $.each(people, function(key, person) {
 console.log("My name is "+person.name+" and I am a "+person.height.feet+" ft "+person.height.inches+" "+person.occupation+"\n");
 });

});
</code></pre>

Output -

My name is Joshua and I am a 5 ft 11 CEO

My name is James and I am a 6 ft 1 programmer

My name is Peter and I am a 4 ft 10 designer

My name is Joshua and I am a 5 ft 11 CEO

Note that outside the loop I have to use the square bracket syntax with a numeric key because this is now an numerically indexed array of objects, and of course inside the loop the numeric key is implied.

blocks|key|1286677|text|只需执行此操作|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1286678|var+key+=+"keyOne";
var+obj+=+{};
obj[key]+=+someValue;|code-block|syntax|javascript|1286679|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Simply do this 

<pre><code>var key = "keyOne";
var obj = {};
obj[key] = someValue;
</code></pre>

blocks|key|1286743|text|数组中的对象：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1286744|var+cars+=+[
++++++++{+"id":+1,+brand:+"Ferrari"+}
++++++++,+{+"id":+2,+brand:+"Lotus"+}
++++++++,+{+"id":+3,+brand:+"Lamborghini"+}
++++];|code-block|syntax|javascript|1286745|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Objects inside an array:

<pre><code>var cars = [
 { "id": 1, brand: "Ferrari" }
 , { "id": 2, brand: "Lotus" }
 , { "id": 3, brand: "Lamborghini" }
 ];
</code></pre>

What's the best way to store a <code>key=&gt;value</code> array in javascript, and how can that be looped through?

The key of each element should be a tag, such as <code>{id}</code> or just <code>id</code> and the value should be the numerical value of the id.

It should either be the element of an existing javascript class, or be a global variable which could easily be referenced through the class.

jQuery can be used.

Best way to store a key=>value array in JavaScript?

jQuery

JSON

在javascript中存储key=>value数组的最好方法是什么，该方法如何循环？每个元素的键应该是一个标签，比如{id}或者仅仅是id，值应该是id的数值。它应该是现有javascript类的元素，或者是可以通过类轻松引用的全局变量。可以使用jQuery。

问在JavaScript中存储key=>value数组的最佳方式是什么？
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