linq.js的用法

linq.js 详细介绍

linq.js 是一个 JavaScript 实现的 LINQ。

主要特性：

实现所有 .NET 4.0 的方法

complete lazy evaluation

full IntelliSense support for VisualStudio

two versions - linq.js and jquery.linq.js (jQuery plugin)

support Windows Script Host

binding for Reactive Extensions for JavaScript(RxJS) and IntelliSense Generator -> see documentation

NuGet install support

示例代码：

var jsonArray = [

    { "user": { "id": 100, "screen_name": "d_linq" }, "text": "to objects" },

    { "user": { "id": 130, "screen_name": "c_bill" }, "text": "g" },

    { "user": { "id": 155, "screen_name": "b_mskk" }, "text": "kabushiki kaisha" },

    { "user": { "id": 301, "screen_name": "a_xbox" }, "text": "halo reach" }

]

// ["b_mskk:kabushiki kaisha", "c_bill:g", "d_linq:to objects"]

var queryResult = Enumerable.From(jsonArray)

    .Where(function (x) { return x.user.id < 200 })

    .OrderBy(function (x) { return x.user.screen_name })

    .Select(function (x) { return x.user.screen_name + ':' + x.text })

    .ToArray();

// shortcut! string lambda selector

var queryResult2 = Enumerable.From(jsonArray)

    .Where("$.user.id < 200")

    .OrderBy("$.user.screen_name")

    .Select("$.user.screen_name + ':' + $.text")

    .ToArray();

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////

用途：方便js操作查询json数据。

下载网址：http://jslinq.codeplex.com/

使用方法：只需要引用linq.js即可。

查询方法：

一、where查询

var myList = [

  { Name: "Jim", Age: 20 },

  { Name: "Kate", Age: 21 },

  { Name: "Lilei", Age: 18 },

  { Name: "John", Age: 14 },

  { Name: "LinTao", Age: 25 }

];

var arrRes = Enumerable.From(myList).Where("x=>x.Name=='Jim'").ToArray();

二、排序：OrderBy

var myList = [

  { Name: "Jim", Age: 20 },

  { Name: "Kate", Age: 21 },

  { Name: "Lilei", Age: 18 },

  { Name: "John", Age: 14 },

  { Name: "LinTao", Age: 25 }

];

var arrRes = Enumerable.From(myList).OrderBy("x=>x.Age").ToArray();//降序OrderByDescending() 

三、去重：Distinct

var myList = [

  { Name: "Jim", Age: 20 },

  { Name: "Kate", Age: 20 },

  { Name: "Lilei", Age: 20 },

  { Name: "John", Age: 14 },

  { Name: "LinTao", Age: 25 }

];

var arrRes = Enumerable.From(myList).Distinct("x=>x.Age").ToArray(); 

四、遍历：ForEach

var myList = [

  { Name: "Jim", Age: 20 },

  { Name: "Kate", Age: 20 },

  { Name: "Lilei", Age: 20 },

  { Name: "John", Age: 14 },

  { Name: "LinTao", Age: 25 }

   ];

   Enumerable.From(myList).ForEach(function(value, index){

        document.write("值="+value+",索引="+index);  

}); 

五、取唯一对象：First、FirstOrDefault、Last、LastOrDefault、Single、SingleOrDefault

var myList = [

  { Name: "Jim", Age: 20 },

  { Name: "Kate", Age: 20 },

  { Name: "Lilei", Age: 20 },

  { Name: "John", Age: 14 },

  { Name: "LinTao", Age: 25 }

];

var arrRes = Enumerable.From(myList).FirstOrDefault("x=>x.Age>18");

　

六、Skip、Take

Enumerable.Range(1,10).Skip(5)//结果[6,7,8,9,10]

Enumerable.Range(1,10).Take(5)//结果[1,2,3,4,5]