Linq学习笔记(1.5)——group、Distinct、Union、Concat、Intersect、Except

using System; using System.Data; using System.Configuration; using System.Linq; using System.Web; using System.Web.Security; using System.Web.UI; using System.Text; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; using System.Collections.Generic; using System.Collections; public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { //用group将集合体分组 Response.Write("<hr>用group将集合体分组：<br>"); List<Student> StudentList = GetStudents(); var students1 = from student in StudentList group student by student.Language into studentsgroup select new {Lang=studentsgroup.Key,member=studentsgroup}; foreach (var g in students1) { Response.Write(string.Format("<div class='result'>Language:{0}</div>",g.Lang)); foreach (var student in g.member) { Response.Write(string.Format("<div class='result'>——{0}</div>", student.Name)); } } //用Distinct将过滤相同项 Response.Write("<hr>用Distinct将过滤相同项：<br>"); var Languages = (from student in StudentList select student.Language) .Distinct(); foreach (var l in Languages) { Response.Write(string.Format("<span class='result'>{0}</span>", l)); } //用Union连接不同集合体 Response.Write("<hr>用Union连接不同集合体：<br>"); string[] stringArray = { "Csharp", "Javascript"}; var Languages2 = (from student in StudentList select student.Language) .Union(stringArray); //Union会自动过滤各集合体中的相同项，无需Distinct foreach (var l in Languages2) { Response.Write(string.Format("<span class='result'>{0}</span>", l)); } //用Concat连接不同集合体 Response.Write("<hr>用Concat连接不同集合体：<br>"); var Languages3 = (from student in StudentList select student.Language) .Concat(stringArray); //Concat不会自动过滤各集合体中的相同项 foreach (var l in Languages3) { Response.Write(string.Format("<span class='result'>{0}</span>", l)); } //用Intersect取不同集合体的相同项(交集) Response.Write("<hr>用Intersect取不同集合体的相同项(交集)：<br>"); string[] Book1Array1 = { "Csharp", "Javascript","FrameWork","Use Compute","WebDesign" }; string[] Book1Array2 = { "Chanese", "English", "Use Compute", "Business", "WebDesign" }; var Books = Book1Array1.Intersect(Book1Array2); foreach (var book in Books) { Response.Write(string.Format("<span class='result'>{0}</span>", book)); } //用Except从集合体中排出和另一个集合体相同的项 Response.Write("<hr>用Except从集合体中排出和另一个集合体相同的项：<br>"); var Books2 = Book1Array1.Except(Book1Array2); foreach (var book in Books2) { Response.Write(string.Format("<span class='result'>{0}</span>", book)); } } //构造一个学生集合体 private List<Student> GetStudents() { List<Student> students = new List<Student> { new Student{ Name="YOUNG", Age=25, Language="Chinese"}, new Student{ Name="JESSIE", Age=21, Language="Scotland"}, new Student{ Name="KELLY", Age=18, Language="English"}, new Student{ Name="JUNE", Age=20, Language="English"}, new Student{ Name="ADRIAN", Age=22, Language="Italy"}, new Student{ Name="BRUCE", Age=17, Language="Scotland"}, new Student{ Name="BRANT", Age=30, Language="Germany"}, new Student{ Name="BEN", Age=25, Language="Chinese"} }; return students; } } //学生类 class Student { public int Age { get; set; } public string Name { get; set; } public string Language { get; set; } }

 

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转自：http://www.cnblogs.com/young18/archive/2007/06/05/772581.html