static void Main(string[] args) { int[] int_array = { 1, 8, 5, 9, 15, 20 }; var filtered = from value in int_array//注意是var，可以帮助我们减少很多麻烦 where value > 4 select value; Console.WriteLine(filtered.GetType());//System.Linq.Enumerable+<WhereIterator>d__0`1[System.Int32] foreach (int i in filtered) { Console.Write(i + "");//8 5 9 15 20 } Console.WriteLine(); Console.WriteLine("The Next:"); double[] double_array={1.6,2.5,1.5,7.5}; IEnumerable<double> double_arrayQuery =//标准格式 from value in double_array where value > 2 select value; Console.WriteLine(double_arrayQuery.GetType());//System.Linq.Enumerable+<WhereIterator>d__0`1[System.Double] foreach (double testQuery in double_arrayQuery) { Console.Write(testQuery+"");//2.5 7.5 } }
static void Main(string[] args){int[] int_array = { 1, 8, 5, 9, 15, 20 };var filtered = from value in int_array//注意是varwhere value > 4orderby value//按默认的规则升序排列select value;Console.WriteLine(filtered.GetType());//System.Linq.Enumerable+<WhereIterator>d__0`1[System.Int32]foreach (int i in filtered){Console.Write(i + "");//5 8 9 15 20}Console.WriteLine();Console.WriteLine("The Next:");double[] double_array={1.6,2.5,1.5,7.5};IEnumerable<double> double_arrayQuery =//标准格式from value in double_arraywhere value > 2orderby value descending//降序排列select value;Console.WriteLine(double_arrayQuery.GetType());//System.Linq.Enumerable+<WhereIterator>d__0`1[System.Double]foreach (double testQuery in double_arrayQuery)//注意这里查询的是哪个变量，是SQL的变量{Console.Write(testQuery+"");//7.5 2.5}string[] names = { "Mr.w","Jack","Angrw"};Console.WriteLine("The names is :");foreach (string nametest in names){Console.Write(nametest + "");}Console.WriteLine();IEnumerable<string> names_query =from name in namesorderby nameselect name;Console.WriteLine("The Orderby of name is :");foreach (string nametest in names_query){Console.Write(nametest + "");}Console.WriteLine();names_query =from name in namesorderby name descendingselect name;Console.WriteLine("The Orderby...Descending of name is :");foreach (string nametest in names_query){Console.Write(nametest + "");}Console.WriteLine();}The Result:/*System.Linq.OrderedEnumerable`2[System.Int32,System.Int32]5 8 9 15 20The Next:System.Linq.OrderedEnumerable`2[System.Double,System.Double]7.5 2.5 The names is :Mr.w Jack AngrwThe Orderby of name is :Angrw Jack Mr.wThe Orderby...Descending of name is :Mr.w Jack Angrw*/
static void Main(string[] args) { int[] int_array = { 1, 8, 5, 9, 15, 20 }; var filtered = from value in int_array//注意是var where value > 4 orderby value//按默认的规则升序排列 select value; Console.WriteLine(filtered.GetType());//System.Linq.Enumerable+<WhereIterator>d__0`1[System.Int32] Display(filtered, "Int"); double[] double_array={1.6,2.5,1.5,7.5}; IEnumerable<double> double_arrayQuery =//标准格式 from value in double_array where value > 2 orderby value descending//降序排列 select value; Console.WriteLine(double_arrayQuery.GetType());//System.Linq.Enumerable+<WhereIterator>d__0`1[System.Double] Display(double_arrayQuery, "Double"); string[] names = { "Mr.w","Jack","Angrw"}; IEnumerable<string> names_query = from name in names orderby name select name; Display(names_query,"String-orderby"); names_query = from name in names orderby name descending select name; Display(names_query, "String-orderby..descending"); } //为了简化我们写成方法调用 static void Display(IEnumerable<string> string_query, string welcome) //下面3个方法起到了方法重载作用 { Console.WriteLine("The {0} is :", welcome); foreach (string test in string_query) { Console.Write(test + ""); } Console.WriteLine(); } static void Display(IEnumerable<int> int_query, string welcome) { Console.WriteLine("The {0} is :", welcome); foreach (int test in int_query) { Console.Write(test + ""); } Console.WriteLine(); } static void Display(IEnumerable<double> double_query, string welcome) { Console.WriteLine("The {0} is :", welcome); foreach (double test in double_query) { Console.Write(test + ""); } Console.WriteLine(); }The Result:/*System.Linq.OrderedEnumerable`2[System.Int32,System.Int32]The Int is :5 8 9 15 20System.Linq.OrderedEnumerable`2[System.Double,System.Double]The Double is :7.5 2.5The String-orderby is :Angrw Jack Mr.wThe String-orderby...descending is :Mr.w Jack Angrw*/
class Program { static void Main(string[] args) { Member[] persons ={ new Member(-10m, 21, "jack"), new Member(25m,25,"An"), new Member(100m,18,"Mr.w"), new Member(3000m,27,"deve") }; Display(persons,"The Array"); var betwtenn100M3000M = from e in persons where e.Pay >= 100m && e.Pay <= 3000m select e; Display(betwtenn100M3000M, "100m-300m"); var PaySort = from e in persons orderby e.Pay //默认是月薪从小到大 select e; Display(PaySort,"The Pay Sort"); var AgeSort = from e in persons orderby e.age descending //年龄从大到小 select e; Display(AgeSort, "The Age Sort"); } static void Display<T>(IEnumerable<T> T_query, string header)//泛型接口 { Console.WriteLine("{0} :", header); foreach (T test in T_query) { Console.WriteLine(test + ""); } Console.WriteLine(); } } class Member//成员 { private decimal pay;// 月薪 public decimal Pay//月薪属性 { get { return pay; } set { if (value >= 0m) { pay = value; } } } public string name;//这里如果不是public 外部将无法访问 public int age; public Member(decimal monthPay, int member_age, string member_name) { name = member_name; age = member_age; Pay = monthPay;//注意这里的大写Pay } public override string ToString()//重写string类的ToString方法 { return string.Format("Name is: {0} Age is:{1} MonthPay is:{2}",name,age,pay); } }The Result:/*The Array :Name is: jack Age is:21 MonthPay is:0Name is: An Age is:25 MonthPay is:25Name is: Mr.w Age is:18 MonthPay is:100Name is: deve Age is:27 MonthPay is:3000100m-300m :Name is: Mr.w Age is:18 MonthPay is:100Name is: deve Age is:27 MonthPay is:3000The Pay Sort :Name is: jack Age is:21 MonthPay is:0Name is: An Age is:25 MonthPay is:25Name is: Mr.w Age is:18 MonthPay is:100Name is: deve Age is:27 MonthPay is:3000The Age Sort :Name is: deve Age is:27 MonthPay is:3000Name is: An Age is:25 MonthPay is:25Name is: jack Age is:21 MonthPay is:0Name is: Mr.w Age is:18 MonthPay is:100*/
