how to query LIST using linq

Question

Suppose if I add person class instance to list and then I need to query the list using linq   List lst new List    lst add new person ID 1 Name  jhon  salary 2500    lst add new person ID 2 Name  Sena  salary 1500    lst add new person ID 3 Name  Max  salary 5500    lst add new person ID 4 Name  Gen  salary 3500      Now I want to query the above list with linq  Please guide me with sample code

User · Answer

Since you haven t given any indication to what you want  here is a link to 101 LINQ samples that use all the different LINQ methods  101 LINQ Samples  Also  you should really really really change your List into a strongly typed list  List lt T gt    properly define T  and add instances of T to your list  It will really make the queries much easier since you won t have to cast everything all the time

User · Answer

Well  the code you ve given is invalid to start with - List is a generic type  and it has an Add method instead of add etc   But you could do something like   List lt Person gt  list   new List lt Person gt        new person ID 1 Name  jhon  salary 2500       new person ID 2 Name  Sena  salary 1500       new person ID 3 Name  Max  salary 5500       new person ID 4 Name  Gen  salary 3500         The  Where  LINQ operator filters a sequence var highEarners   list Where p   gt  p salary  gt  3000    foreach  var person in highEarners        Console WriteLine person Name       If you want to learn details of what all the LINQ operators do  and how they can be implemented in LINQ to Objects  you might be interested in my Edulinq blog series

User · Answer

I would also suggest LinqPad as a convenient way to tackle with Linq for both advanced and beginners   Example

User · Answer

var persons   new List lt Person gt                new Person  ID   1  Name    jhon   Salary   2500           new Person  ID   2  Name    Sena   Salary   1500           new Person  ID   3  Name    Max   Salary   5500           new Person  ID   4  Name    Gen   Salary   3500          var acertainperson   persons Where p   gt  p Name     jhon   First    Console WriteLine   0    1  points       acertainperson Name  acertainperson Salary    jhon  2500 points  var doingprettywell   persons Where p   gt  p Salary  gt  2000               foreach  var person in doingprettywell                                Console WriteLine   0    1  points                       person Name  person Salary                  jhon  2500 points Max  5500 points Gen  3500 points          var astupidcalc   from p in persons                           where p ID  gt  2                           select new                                                                                 Name   p Name                                           Bobos   p Salary p ID                                           Bobotype    bobos                                                  foreach  var person in astupidcalc                        Console WriteLine   0    1   2                    person Name  person Bobos  person Bobotype              Max  16500 bobos Gen  14000 bobos

[c#] how to query LIST using linq

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