blocks|key|175770|text|是的，Array.map()或$.map()也做同样的事情。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|175771|//array.map:
var+ids+=+this.fruits.map(function(v){
++++return+v.Id;
});

//jQuery.map:
var+ids2+=+$.map(this.fruits,+function+(v){
++++return+v.Id;
});

console.log(ids,+ids2);|code-block|syntax|javascript|175772|http://jsfiddle.net/NsCXJ/1/|175773|由于较旧的浏览器不支持array.map，因此我建议您坚持使用jQuery方法。|175774|如果出于某些原因，您更喜欢另一个，您可以随时为旧浏览器支持添加polyfill。|175775|您也可以随时向数组原型添加自定义方法：|175776|Array.prototype.select+=+function(expr){
++++var+arr+=+this;
++++//do+custom+stuff
++++return+arr.map(expr);+//or+$.map(expr);
};

var+ids+=+this.fruits.select(function(v){
++++return+v.Id;
});|175777|175778|传递字符串时使用函数构造函数的扩展版本。一些可以玩玩的东西：|175779|Array.prototype.select+=+function(expr){
++++var+arr+=+this;

++++switch(typeof+expr){

++++++++case+'function':
++++++++++++return+$.map(arr,+expr);
++++++++++++break;

++++++++case+'string':

++++++++++++try{

++++++++++++++++var+func+=+new+Function(expr.split('.')[0],+
+++++++++++++++++++++++++++++++++++++++'return+'+%2B+expr+%2B+';');
++++++++++++++++return+$.map(arr,+func);

++++++++++++}catch(e){

++++++++++++++++return+null;
++++++++++++}

++++++++++++break;

++++++++default:
++++++++++++throw+new+ReferenceError('expr+not+defined+or+not+supported');
++++++++++++break;
++++}

};

console.log(fruits.select('x.Id'));|175780|http://jsfiddle.net/aL85j/|175781|更新：|style|BOLD|175782|由于这已经成为一个流行的答案，我添加了类似的我的where()+%2B+firstOrDefault()。这些也可以用于基于字符串的函数构造方法(这是最快的)，但这里是另一种使用对象文字作为过滤器的方法：|CODE|175783|Array.prototype.where+=+function+(filter)+{

++++var+collection+=+this;

++++switch(typeof+filter)+{+

++++++++case+'function':+
++++++++++++return+$.grep(collection,+filter);+

++++++++case+'object':
++++++++++++for(var+property+in+filter)+{
++++++++++++++if(!filter.hasOwnProperty(property))+
++++++++++++++++++continue;+//+ignore+inherited+properties

++++++++++++++collection+=+$.grep(collection,+function+(item)+{
++++++++++++++++++return+item[property]+===+filter[property];
++++++++++++++});
++++++++++++}
++++++++++++return+collection.slice(0);+//+copy+the+array+
++++++++++++++++++++++++++++++++++++++//+(in+case+of+empty+object+filter)

++++++++default:+
++++++++++++throw+new+TypeError('func+must+be+either+a'+%2B
++++++++++++++++'function+or+an+object+of+properties+and+values+to+filter+by');+
++++}
};


Array.prototype.firstOrDefault+=+function(func){
++++return+this.where(func)[0]+%7C%7C+null;
};|175784|用法：|175785|var+persons+=+[{+name:+'foo',+age:+1+},+{+name:+'bar',+age:+2+}];

//+returns+an+array+with+one+element:
var+result1+=+persons.where({+age:+1,+name:+'foo'+});

//+returns+the+first+matching+item+in+the+array,+or+null+if+no+match
var+result2+=+persons.firstOrDefault({+age:+1,+name:+'foo'+});+|175786|这是一个比较函数构造函数和对象字面速度的jsperf+test。如果您决定使用前者，请记住正确地引用字符串。|175787|我个人的偏好是在过滤1-2个属性时使用基于对象文字的解决方案，并传递一个回调函数来进行更复杂的过滤。|175788|在将方法添加到原生对象原型时，我将用两个一般技巧来结束这一点：|175789|175790|在覆盖之前检查现有方法的出现情况，例如：|ordered-list-item|175791|175792|if(!Array.prototype.where)+{+++++Array.prototype.where+=+...|175793|If您不需要支持IE8或更低版本，请使用Object.defineProperty定义方法，使其不可枚举。如果有人在数组上使用了for..in+(这首先是错误的)，他们也会迭代可枚举的属性。只是提醒一下。|unordered-list-item|175794|175795|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map|1|http://api.jquery.com/jQuery.map/|2|3|4|http://jsperf.com/3-kinds-of-grepping|5|https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty^0|3|B|0|F|7|1|0|0|0|S|2|0|0|0|0|0|0|0|0|0|Q|3|0|0|3|0|O|7|Y|G|0|0|0|0|K|B|4|0|0|0|0|0|0|0|1O|0|1S|7|K|L|5|0|0^^$0|@$1|2|3|4|5|6|7|29|8|@]|9|@$A|2A|B|2B|1|2C]|$A|2D|B|2E|1|2F]]|C|$]]|$1|D|3|E|5|F|7|2G|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|2H|8|@]|9|@$A|2I|B|2J|1|2K]]|C|$]]|$1|K|3|L|5|6|7|2L|8|@]|9|@]|C|$]]|$1|M|3|N|5|6|7|2M|8|@]|9|@]|C|$]]|$1|O|3|P|5|6|7|2N|8|@]|9|@]|C|$]]|$1|Q|3|R|5|F|7|2O|8|@]|9|@]|C|$G|H]]|$1|S|3|-4|5|6|7|2P|8|@]|9|@]|C|$]]|$1|T|3|U|5|6|7|2Q|8|@]|9|@]|C|$]]|$1|V|3|W|5|F|7|2R|8|@]|9|@]|C|$G|H]]|$1|X|3|Y|5|6|7|2S|8|@]|9|@$A|2T|B|2U|1|2V]]|C|$]]|$1|Z|3|10|5|6|7|2W|8|@$A|2X|B|2Y|11|12]]|9|@]|C|$]]|$1|13|3|14|5|6|7|2Z|8|@$A|30|B|31|11|15]|$A|32|B|33|11|15]]|9|@]|C|$]]|$1|16|3|17|5|F|7|34|8|@]|9|@]|C|$G|H]]|$1|18|3|19|5|6|7|35|8|@]|9|@]|C|$]]|$1|1A|3|1B|5|F|7|36|8|@]|9|@]|C|$G|H]]|$1|1C|3|1D|5|6|7|37|8|@]|9|@$A|38|B|39|1|3A]]|C|$]]|$1|1E|3|1F|5|6|7|3B|8|@]|9|@]|C|$]]|$1|1G|3|1H|5|6|7|3C|8|@]|9|@]|C|$]]|$1|1I|3|-4|5|6|7|3D|8|@]|9|@]|C|$]]|$1|1J|3|1K|5|1L|7|3E|8|@]|9|@]|C|$]]|$1|1M|3|-4|5|6|7|3F|8|@]|9|@]|C|$]]|$1|1N|3|1O|5|6|7|3G|8|@$A|3H|B|3I|11|15]]|9|@]|C|$]]|$1|1P|3|1Q|5|1R|7|3J|8|@$A|3K|B|3L|11|15]]|9|@$A|3M|B|3N|1|3O]]|C|$]]|$1|1S|3|-4|5|6|7|3P|8|@]|9|@]|C|$]]|$1|1T|3|-4|5|6|7|3Q|8|@]|9|@]|C|$]]]|1U|$1V|$5|1W|1X|1Y|C|$1Z|20]]|21|$5|1W|1X|1Y|C|$1Z|22]]|23|$5|1W|1X|1Y|C|$1Z|J]]|24|$5|1W|1X|1Y|C|$1Z|Y]]|25|$5|1W|1X|1Y|C|$1Z|26]]|27|$5|1W|1X|1Y|C|$1Z|28]]]]

Yes, <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map" rel="noreferrer">Array.map()</a> or <a href="http://api.jquery.com/jQuery.map/" rel="noreferrer">$.map()</a> does the same thing.

<pre><code>//array.map:
var ids = this.fruits.map(function(v){
 return v.Id;
});

//jQuery.map:
var ids2 = $.map(this.fruits, function (v){
 return v.Id;
});

console.log(ids, ids2);
</code></pre>

<a href="http://jsfiddle.net/NsCXJ/1/" rel="noreferrer">http://jsfiddle.net/NsCXJ/1/</a>

Since array.map isn't supported in older browsers, I suggest that you stick with the jQuery method.

If you prefer the other one for some reason you could always add a polyfill for old browser support.

You can always add custom methods to the array prototype as well:

<pre><code>Array.prototype.select = function(expr){
 var arr = this;
 //do custom stuff
 return arr.map(expr); //or $.map(expr);
};

var ids = this.fruits.select(function(v){
 return v.Id;
});
</code></pre>

<hr>

An extended version that uses the function constructor if you pass a string. Something to play around with perhaps:

<pre><code>Array.prototype.select = function(expr){
 var arr = this;

 switch(typeof expr){

 case 'function':
 return $.map(arr, expr);
 break;

 case 'string':

 try{

 var func = new Function(expr.split('.')[0], 
 'return ' + expr + ';');
 return $.map(arr, func);

 }catch(e){

 return null;
 }

 break;

 default:
 throw new ReferenceError('expr not defined or not supported');
 break;
 }

};

console.log(fruits.select('x.Id'));
</code></pre>

<a href="http://jsfiddle.net/aL85j/" rel="noreferrer">http://jsfiddle.net/aL85j/</a>

Update:

Since this has become such a popular answer, I'm adding similar my <code>where()</code> + <code>firstOrDefault()</code>. These could also be used with the string based function constructor approach (which is the fastest), but here is another approach using an object literal as filter:

<pre><code>Array.prototype.where = function (filter) {

 var collection = this;

 switch(typeof filter) { 

 case 'function': 
 return $.grep(collection, filter); 

 case 'object':
 for(var property in filter) {
 if(!filter.hasOwnProperty(property)) 
 continue; // ignore inherited properties

 collection = $.grep(collection, function (item) {
 return item[property] === filter[property];
 });
 }
 return collection.slice(0); // copy the array 
 // (in case of empty object filter)

 default: 
 throw new TypeError('func must be either a' +
 'function or an object of properties and values to filter by'); 
 }
};


Array.prototype.firstOrDefault = function(func){
 return this.where(func)[0] || null;
};
</code></pre>

Usage:

<pre><code>var persons = [{ name: 'foo', age: 1 }, { name: 'bar', age: 2 }];

// returns an array with one element:
var result1 = persons.where({ age: 1, name: 'foo' });

// returns the first matching item in the array, or null if no match
var result2 = persons.firstOrDefault({ age: 1, name: 'foo' }); 
</code></pre>

Here is a <a href="http://jsperf.com/3-kinds-of-grepping" rel="noreferrer">jsperf test</a> to compare the function constructor vs object literal speed. If you decide to use the former, keep in mind to quote strings correctly.

My personal preference is to use the object literal based solutions when filtering 1-2 properties, and pass a callback function for more complex filtering.

I'll end this with 2 general tips when adding methods to native object prototypes:

<ol>
<li>Check for occurrence of existing methods before overwriting e.g.:

<code>if(!Array.prototype.where) {
 Array.prototype.where = ...</code></li>
<li>If you don't need to support IE8 and below, define the methods using <a href="https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty" rel="noreferrer">Object.defineProperty</a> to make them non-enumerable. If someone used <code>for..in</code> on an array (which is wrong in the first place)
they will iterate enumerable properties as well. Just a heads up.</li>
</ol>

blocks|key|174969|text|看一看underscore.js，它提供了许多类似linq的函数。在您给出的示例中，您将使用map函数。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|174970|entityMap|0|LINK|mutability|MUTABLE|url|http://underscorejs.org/^0|3|D|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Take a peek at <a href="http://underscorejs.org/" rel="nofollow">underscore.js</a> which provides many linq like functions. In the example you give you would use the map function.

blocks|key|2993732|text|由于您正在使用knockout，因此应该考虑使用knockout实用函数arrayMap()和它的其他数组实用函数。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2993733|下面是数组实用函数及其等效的LINQ方法的列表：|2993734|arrayFilter()+->+Where()
arrayFirst()+->+First()
arrayForEach()+->+(no+direct+equivalent)
arrayGetDistictValues()+->+Distinct()
arrayIndexOf()+->+IndexOf()
arrayMap()+->+Select()
arrayPushAll()+->+(no+direct+equivalent)
arrayRemoveItem()+->+(no+direct+equivalent)
compareArrays()+->+(no+direct+equivalent)|code-block|syntax|javascript|2993735|因此，您可以在您的示例中执行以下操作：|2993736|var+mapped+=+ko.utils.arrayMap(selectedFruits,+function+(fruit)+{
++++return+fruit.id;
});|2993737|如果你想在javascript中有一个类似LINQ的接口，你可以使用像linq.js这样的库，它为许多LINQ方法提供了一个很好的接口。|2993738|var+mapped+=+Enumerable.from(selectedFruits)
++++.select("$.id")+//+shorthand+for+`x+=>+x.id`
++++.toArray();|2993739|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/mihaifm/linq^0|10|A|0|0|0|0|0|Z|7|0|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@$9|13|A|14|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|15|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|16|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|17|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|18|8|@]|D|@]|E|$K|L]]|$1|Q|3|R|5|6|7|19|8|@]|D|@$9|1A|A|1B|1|1C]]|E|$]]|$1|S|3|T|5|J|7|1D|8|@]|D|@]|E|$K|L]]|$1|U|3|-4|5|6|7|1E|8|@]|D|@]|E|$]]]|V|$W|$5|X|Y|Z|E|$10|11]]]]

Since you're using knockout, you should consider using the knockout utility function <code>arrayMap()</code> and it's other array utility functions.
Here's a listing of array utility functions and their equivalent LINQ methods:
<pre><code>arrayFilter() -&gt; Where()
arrayFirst() -&gt; First()
arrayForEach() -&gt; (no direct equivalent)
arrayGetDistictValues() -&gt; Distinct()
arrayIndexOf() -&gt; IndexOf()
arrayMap() -&gt; Select()
arrayPushAll() -&gt; (no direct equivalent)
arrayRemoveItem() -&gt; (no direct equivalent)
compareArrays() -&gt; (no direct equivalent)
</code></pre>
So what you could do in your example is this:
<pre><code>var mapped = ko.utils.arrayMap(selectedFruits, function (fruit) {
 return fruit.id;
});
</code></pre>
If you want a LINQ like interface in javascript, you could use a library such as <a href="https://github.com/mihaifm/linq" rel="nofollow noreferrer">linq.js</a> which offers a nice interface to many of the LINQ methods.
<pre><code>var mapped = Enumerable.from(selectedFruits)
 .select(&quot;$.id&quot;) // shorthand for `x =&gt; x.id`
 .toArray();
</code></pre>

blocks|key|177414|text|我已经在TsLinq.codeplex.com下为TypeScript构建了一个Linq库，你也可以将它用于普通的javascript。该库比Linq.js快2-3倍，并包含所有Linq方法的单元测试。也许你可以复习一下。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|177415|entityMap|0|LINK|mutability|MUTABLE|url|http://tslinq.codeplex.com/^0|4|J|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

I have build a Linq library for TypeScript under <a href="http://TsLinq.codeplex.com" rel="nofollow">TsLinq.codeplex.com</a> that you can use for plain javascript too. That library is 2-3 times faster than Linq.js and contains unit tests for all Linq methods. Maybe you could review that one.

blocks|key|177417|text|我知道这是一个迟来的答案，但它对我很有用！最后，使用$.grep函数可以模拟linq+where()。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|177418|Linq：|177419|var+maleNames+=+people
.Where(p+=>+p.Sex+==+"M")
.Select(p+=>+p.Name)|code-block|syntax|javascript|177420|Javascript：|177421|//+replace+where++with+$.grep
//+++++++++select+with+$.map
var+maleNames+=+$.grep(people,+function+(p)+{+return+p.Sex+==+'M';+})
++++++++++++.map(function+(p)+{+return+p.Name;+});|177422|entityMap^0|Q|6|17|7|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|X|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|Y|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|Z|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|10|8|@]|D|@]|E|$K|L]]|$1|Q|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|R|$]]

I know it is a late answer but it was useful to me! Just to complete, using the <code>$.grep</code> function you can emulate the linq <code>where()</code>.

Linq:

<pre><code>var maleNames = people
.Where(p =&gt; p.Sex == "M")
.Select(p =&gt; p.Name)
</code></pre>

Javascript:

<pre><code>// replace where with $.grep
// select with $.map
var maleNames = $.grep(people, function (p) { return p.Sex == 'M'; })
 .map(function (p) { return p.Name; });
</code></pre>

blocks|key|175897|text|Javascript具有类似linq的语法，并为map和indexOf等函数提供了多个填充，并且是专门为在Dinqyjs中使用数组而设计的。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|175898|entityMap|0|LINK|mutability|MUTABLE|url|http://dinqyjs.com/^0|1H|7|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

<a href="http://dinqyjs.com" rel="nofollow" title="Dinqyjs">Dinqyjs</a> has a linq-like syntax and provides polyfills for functions like map and indexOf, and has been designed specifically for working with arrays in Javascript.

blocks|key|175010|text|您也可以尝试使用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|175011|在中，|175012|selectedFruits.select(fruit=>fruit.id);|code-block|syntax|javascript|175013|将会是|175014|Enumerable.From(selectedFruits).Select(function+(fruit)+{+return+fruit.id;++});|175015|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

You can also try <a href="http://linqjs.codeplex.com/" rel="noreferrer"><code>linq.js</code></a>

In <a href="http://linqjs.codeplex.com/" rel="noreferrer"><code>linq.js</code></a> your

<pre><code>selectedFruits.select(fruit=&gt;fruit.id);
</code></pre>

will be 

<pre><code>Enumerable.From(selectedFruits).Select(function (fruit) { return fruit.id; });
</code></pre>

blocks|key|2993799|text|ES6方式：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2993800|let+people+=+[{firstName:'Alice',lastName:'Cooper'},{firstName:'Bob',age:'Dylan'}];
let+names+=+Array.from(people,+p+=>+p.firstName);
for+(let+name+of+names)+{
++console.log(name);
}|code-block|syntax|javascript|2993801|另请访问：https://jsfiddle.net/52dpucey/|offset|length|2993802|entityMap|0|LINK|mutability|MUTABLE|url|https://jsfiddle.net/52dpucey/^0|0|0|5|U|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

The ES6 way:

<pre><code>let people = [{firstName:'Alice',lastName:'Cooper'},{firstName:'Bob',age:'Dylan'}];
let names = Array.from(people, p =&gt; p.firstName);
for (let name of names) {
 console.log(name);
}
</code></pre>

also at: <a href="https://jsfiddle.net/52dpucey/" rel="noreferrer">https://jsfiddle.net/52dpucey/</a>

blocks|key|175904|text|您可以尝试使用manipula包，它实现了所有的C#+LINQ方法并保存了它的语法：https://github.com/litichevskiydv/manipula|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|175905|https://www.npmjs.com/package/manipula|175906|您的示例selectedFruits.select(fruit=>fruit.id);将使用manipula实现为|175907|Manipula.from(selectedFruits).select(fruit=>fruit.id);|code-block|syntax|javascript|175908|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/litichevskiydv/manipula|1^0|7|8|16|16|0|0|0|12|1|0|4|13|0|0^^$0|@$1|2|3|4|5|6|7|X|8|@$9|Y|A|Z|B|C]]|D|@$9|10|A|11|1|12]]|E|$]]|$1|F|3|G|5|6|7|13|8|@]|D|@$9|14|A|15|1|16]]|E|$]]|$1|H|3|I|5|6|7|17|8|@$9|18|A|19|B|C]]|D|@]|E|$]]|$1|J|3|K|5|L|7|1A|8|@]|D|@]|E|$M|N]]|$1|O|3|-4|5|6|7|1B|8|@]|D|@]|E|$]]]|P|$Q|$5|R|S|T|E|$U|V]]|W|$5|R|S|T|E|$U|G]]]]

You can try <code>manipula</code> package, which implement all of C# LINQ methods and save its syntax:
<a href="https://github.com/litichevskiydv/manipula" rel="nofollow noreferrer">https://github.com/litichevskiydv/manipula</a>

<a href="https://www.npmjs.com/package/manipula" rel="nofollow noreferrer">https://www.npmjs.com/package/manipula</a>

Your example <code>selectedFruits.select(fruit=&gt;fruit.id);</code>
will be implemented with manipula as

<pre><code>Manipula.from(selectedFruits).select(fruit=&gt;fruit.id);
</code></pre>

blocks|key|173763|text|我现在回答的是问题的标题，而不是较具体的原问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|173764|随着Javascript的新特性，如迭代器、生成器函数和对象，像LINQ+for+Javascript这样的东西成为可能。请注意，例如，linq.js使用了一种完全不同的方法，使用正则表达式，可能是为了克服当时该语言缺乏支持的问题。|173765|话虽如此，我已经为Javascript编写了一个LINQ库，你可以在https://github.com/Siderite/LInQer上找到它。在https://siderite.dev/blog/linq-in-javascript-linqer上发表评论和讨论。|offset|length|173766|从前面的回答来看，似乎只有Manipula才是Javascript中LINQ端口的预期。|173767|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/Siderite/LInQer|1|https://siderite.dev/blog/linq-in-javascript-linqer^0|0|0|Y|Y|0|22|1F|1|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|U|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|V|8|@]|9|@$F|W|G|X|1|Y]|$F|Z|G|10|1|11]]|A|$]]|$1|H|3|I|5|6|7|12|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|13|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|Q]]|R|$5|M|N|O|A|$P|S]]]]

I am answering the title of the question rather than the original question which was more specific.

With the new features of Javascript like iterators and generator functions and objects, something like LINQ for Javascript becomes possible. Note that linq.js, for example, uses a completely different approach, using regular expressions, probably to overcome the lack of support in the language at the time.

With that being said, I've written a LINQ library for Javascript and you can find it at <a href="https://github.com/Siderite/LInQer" rel="nofollow noreferrer">https://github.com/Siderite/LInQer</a>. Comments and discussion at <a href="https://siderite.dev/blog/linq-in-javascript-linqer" rel="nofollow noreferrer">https://siderite.dev/blog/linq-in-javascript-linqer</a>.

From previous answers, only Manipula seems to be what one would expect from a LINQ port in Javascript.

blocks|key|2993961|text|看看fluent，它支持LINQ所做的几乎所有事情，并且是基于可迭代的--所以它可以处理映射，生成器函数，数组，所有可迭代的东西。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|2993962|entityMap|0|LINK|mutability|MUTABLE|url|https://www.npmjs.com/package/fluent-iterable^0|2|6|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Take a look at <a href="https://www.npmjs.com/package/fluent-iterable" rel="nofollow noreferrer">fluent</a>, it supports almost everything LINQ does and based on iterables - so it works with maps, generator functions, arrays, everything iterable.

blocks|key|175057|text|与C#+Select最相似的是map函数。只需使用：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|175058|var+ids+=+selectedFruits.map(fruit+=>+fruit.id);|code-block|syntax|javascript|175059|从selectedFruits数组中选择所有ids。|175060|它不需要任何外部依赖，只需要纯JavaScript。您可以在此处找到map文档：https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map|175061|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map^0|4|6|F|3|0|0|1|E|0|Y|3|14|2I|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|11|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|12|8|@$9|13|A|14|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|15|8|@$9|16|A|17|B|C]]|D|@$9|18|A|19|1|1A]]|E|$]]|$1|O|3|-4|5|6|7|1B|8|@]|D|@]|E|$]]]|P|$Q|$5|R|S|T|E|$U|V]]]]

The most similar C# <code>Select</code> analogue would be a <code>map</code> function.
Just use:

<pre class="lang-js prettyprint-override"><code>var ids = selectedFruits.map(fruit =&gt; fruit.id);
</code></pre>

to select all ids from <code>selectedFruits</code> array.

It doesn't require any external dependencies, just pure JavaScript. You can find <code>map</code> documentation here: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map" rel="nofollow noreferrer">https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map</a>

blocks|key|2993994|text|我不得不合并这个不错的答案。它揭示了一些类似的东西；|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2993995|扩展；|2993996|+Array.prototype.where+=+function+(filter)+{

++++++++++++++++++++++++++++++++var+collection+=+this;

++++++++++++++++++++++++++++++++switch+(typeof+filter)+{

++++++++++++++++++++++++++++++++++++case+'function':
++++++++++++++++++++++++++++++++++++++++return+$.grep(collection,+filter);

++++++++++++++++++++++++++++++++++++case+'object':
++++++++++++++++++++++++++++++++++++++++for+(var+property+in+filter)+{
++++++++++++++++++++++++++++++++++++++++++++if+(!filter.hasOwnProperty(property))
++++++++++++++++++++++++++++++++++++++++++++++++continue;+//+ignore+inherited+properties

++++++++++++++++++++++++++++++++++++++++++++collection+=+$.grep(collection,+function+(item)+{
++++++++++++++++++++++++++++++++++++++++++++++++return+item[property]+===+filter[property];
++++++++++++++++++++++++++++++++++++++++++++});
++++++++++++++++++++++++++++++++++++++++}
++++++++++++++++++++++++++++++++++++++++return+collection.slice(0);+//+copy+the+array+
++++++++++++++++++++++++++++++++++++//+(in+case+of+empty+object+filter)

++++++++++++++++++++++++++++++++++++default:
++++++++++++++++++++++++++++++++++++++++throw+new+TypeError('func+must+be+either+a'+%2B
++++++++++++++++++++++++++++++++++++++++++++'function+or+an+object+of+properties+and+values+to+filter+by');
++++++++++++++++++++++++++++++++}
++++++++++++++++++++++++++++};|code-block|syntax|javascript|2993997|用法；|2993998|masterTableView.get_dataItems().where(function+(t)+{
if+(t.findElement("_invoiceGridCheckbox").checked)+{
++++invoiceIds.push(t.getDataKeyValue("Id"));
++}
});|2993999|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Had to merge this nice answers. It revealed something like that;
Extension;
<pre><code> Array.prototype.where = function (filter) {

 var collection = this;

 switch (typeof filter) {

 case 'function':
 return $.grep(collection, filter);

 case 'object':
 for (var property in filter) {
 if (!filter.hasOwnProperty(property))
 continue; // ignore inherited properties

 collection = $.grep(collection, function (item) {
 return item[property] === filter[property];
 });
 }
 return collection.slice(0); // copy the array 
 // (in case of empty object filter)

 default:
 throw new TypeError('func must be either a' +
 'function or an object of properties and values to filter by');
 }
 };
</code></pre>
Usage;
<pre><code>

masterTableView.get_dataItems().where(function (t) {
if (t.findElement(&quot;_invoiceGridCheckbox&quot;).checked) {
 invoiceIds.push(t.getDataKeyValue(&quot;Id&quot;));
 }
});
</code></pre>

blocks|key|175074|text|至于2021年，有一个完整的LINQ+to+object实现，它是用ECMAScript+(javascript)的最新功能编写的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|175075|Github存储库是：https://github.com/IlanAmoyal/WebPartyLinq|offset|length|175076|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/IlanAmoyal/WebPartyLinq^0|0|B|16|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@$D|P|E|Q|1|R]]|A|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]]]

As for 2021, there is a full implementation of LINQ to object written with the latest feature of ECMAScript (javascript).
The Github repository is:
<a href="https://github.com/IlanAmoyal/WebPartyLinq" rel="nofollow noreferrer">https://github.com/IlanAmoyal/WebPartyLinq</a>

Following this question here :

<blockquote>
 <a href="https://stackoverflow.com/questions/8180744/using-the-checked-binding-in-knockout-with-a-list-of-checkboxes-checks-all-the-c">Using the checked binding in knockout with a list of checkboxes checks all the checkboxes</a>
</blockquote>

I've created some checkboxes using knockout that allow selection from an array.
working fiddle taken from above post:

<blockquote>
 <a href="http://jsfiddle.net/NsCXJ/" rel="noreferrer">http://jsfiddle.net/NsCXJ/</a>
</blockquote>

Is there a simple way of creating an array of just the fruit's ID's?

I'm more at home with C# where I would do something along the lines of <code>selectedFruits.select(fruit=&gt;fruit.id);</code>

Is there some method/ready made function for doing something similar with javascript/jquery? Or would the simplest option be to loop through the list and create a second array?
I intend to post the array back to the server in JSON so am trying to minimize the data sent.

Javascript Equivalent to C# LINQ Select

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋 

腾讯云代码助手

CODING DevOps

Cloud Studio

SDK中心

API中心

命令行工具

下面是这个问题： 我使用knockout创建了一些复选框，允许从数组中进行选择。工作小提琴取自上述帖子： 有没有一种简单的方法来创建一个只包含水果ID的数组？我更熟悉C#，在那里我会按照selectedFruits.select(fruit=>fruit.id);的思路做一些事情有没有一些方法/现成的函数可以用来做一些...

问相当于C# LINQ Select的Javascript
EN

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问相当于C# LINQ Select的JavascriptEN