Lambda expressions are used to filter objects.

Lambda expressions are used to filter objects.
1 public class Person: BaseDomain 2 {3 long _ id; 4 string firstName; 5 string secondName; 6 string comments; 7 8 public Person () 9 {} 10 11 public Person (long id) 12 {13 this. _ id = id; 14} 15 public Person (long id, string firstName, string secondName) 16 {17 this. _ id = id; 18 this. firstName = firstName; 19 this. secondName = secondName; 20 comments = String. empty; 21} 22 public Person (long id, string firstName, string secondName, string comments) 23: this (id, firstName, secondName) 24 {25 this. comments = comments; 26} 27 28 public string FirstName29 {30 get {return firstName;} 31 set {firstName = value ;} 32} 33 public string SecondName34 {35 get {return secondName;} 36 set {secondName = value;} 37} 38 public string Comments39 {40 get {return comments ;} 41 set {comments = value;} 42} 43 public override string ToString () 44 {45 return string. format ("FirstName: {0} \ tSecondName: {1} \ tComment: {2}", this. firstName, this. secondName, this. comments); 46} 47}View Code

The above is a simple type required for testing: Person

1 var list = new List <Person> (5); 2 list. add (new Person (1, "Bite gold", "Cheng", "guy with an ax"); 3 list. add (new Person (2, "Bite gold", "Cheng", "guy with an ax"); 4 list. add (new Person (3, "mink Chan", "King", "3 skills very powerful"); 5 list. add (new Person (4, "Zhao Jun", "Li", "suitable for group battles"); 6 list. add (new Person (5, "Arthur", "Mao", ""); 7 8 // deduplication, you must first introduce the "using System. linq; "9 var result_list = list. groupBy (obj => obj. firstName ). select (g => g. first ()). toList (); 10 11 foreach (var item in result_list) 12 {13 Console. writeLine (item); 14}View Code