Trending September 2023 # How Where Works In Linq # Suggested October 2023 # Top 17 Popular

You are reading the article How Where Works In Linq updated in September 2023 on the website Dacvumuahe.com. We hope that the information we have shared is helpful to you. If you find the content interesting and meaningful, please share it with your friends and continue to follow and support us for the latest updates. Suggested October 2023 How Where Works In Linq

Introduction to LINQ Where

LINQ Where is a LINQ extension method which is used to filter the collection of elements based on the given condition. The condition can be precise as Func delegate type or in the lambda expression. This will be applicable in method syntax as well as in query syntax. In a single query, we can do multiple where extension methods.

Start Your Free Software Development Course

Web development, programming languages, Software testing & others

Syntax of LINQ Where

Example:

Code:

var _querySyntax = from s in employeeList select emp.empName;

How Where Works in LINQ?

The main purpose of LINQ where is used to filter elements based on the conditions. It comes under the filtering operator category. It applies in both method and query syntax whereas method syntax requires the lambda expression and query syntax requires only the expression. The LINQ Where is used to limit the number of records from select, update, delete statements.

Given below are few examples of LINQ where code the list of elements in the collection.

1. Sequence of strings with single condition

In Lambda Expression we were getting the result of course names with the condition of the beginning letter start with “C”.

In Query Expression, same as above criteria.

Var result=from c in _CourseName where c.StartsWith("C") select c;

We can display the result by using foreach to listing the items, the output will be C and C++.

foreach(var items in result) console.WriteLine(item); 2. Sequence of strings with multiple conditions

In this collection it retrieves the items based on given multiple criteria, it checks the length of the character which is more than 3 characters, and also it checks the beginning letter which should not start with “J”.

In Lambda Expression we were getting the result of course names with the condition of the beginning letter not starts with “J” and the length of the string should be more than 3.

Var result=from c in _CourseName select c;

We can display the result by using foreach to listing the items, the output will be “DotNet”, “Android”.

foreach(var items in result) console.WriteLine(item); 3. Sequence of objects with single conditions

Employee class to retrieve the records based on single where condition.

public class EmployeeClass { public int emp_id { get; set; } public string emp_name { get; set; } public int emp_salary { get; set; } } { new EmployeeClass() { emp _id = 1001, emp _name = "Smith", emp _salary = 30000}, new EmployeeClass() { emp _id = 1002, emp _name = "Sasha", emp _salary = 27000}, new EmployeeClass() { emp _id = 1003, emp _name = "Ricky", emp _salary = 55000}, new EmployeeClass() { emp _id = 1004, emp _name = "Peter", emp _salary = 95000} };

In Lambda Expression we were getting the result of employeeList with the condition of the employee salary greater than 50000.

In Query Expression, same as above criteria.

Var result=from emp in employeeList select emp;

We can display the result by using foreach to listing the items; the output will be “Ricky”, “Peter”.

foreach(var items in result) console.WriteLine(item. emp _name); 4. Sequence of numbers with multiple where

In this example, the Employee Class is listed to retrieve the records using multiple where condition applied.

Example:

{ new EmployeeClass() { emp _id = 1001, emp _name = “Smith”, emp _salary = 30000}, new EmployeeClass() { emp _id = 1002, emp _name = “Sasha”, emp _salary = 27000}, new EmployeeClass() { emp _id = 1003, emp _name = “Ricky”, emp _salary = 42000}, new EmployeeClass() { emp _id = 1004, emp _name = “Peter”, emp _salary = 95000} };

In Query Expression, same as above criteria.

Var result=from e in employeeList where e.emp_salary<50000 where e.emp_name.StartsWith("S") select e;

We can display the result by using foreach to listing the items, the output will be “Smith”, “Sasha”.

foreach(var items in result) console.WriteLine(item.emp_name); Example of LINQ Where

Given below is the example mentioned:

Code:

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace Console_LINQWhere { class ProductClass { public int P_ID {get; set;} public string P_Category { get; set; } public string P_Name { get; set; } public int P_Cost { get; set; } } class Program { static void Main(string[] args) { P_List.Add(new ProductClass { P_ID = 1005, P_Category = "Snacks", P_Name = "Biscuits", P_Cost = 20 }); P_List.Add(new ProductClass { P_ID = 1006, P_Category = "Snacks", P_Name = "Dates", P_Cost = 60}); P_List.Add(new ProductClass { P_ID = 1007, P_Category = "Snacks", P_Name = "Honey", P_Cost = 110 }); P_List.Add(new ProductClass { P_ID = 1008, P_Category = "Snacks", P_Name = "Chips", P_Cost = 35 }); P_List.Add(new ProductClass { P_ID = 1009, P_Category = "Stationery", P_Name = "A4 Sheet Bunddle", P_Cost = 100 }); P_List.Add(new ProductClass { P_ID = 1010, P_Category = "Stationery", P_Name = "Pencil Box", P_Cost = 52}); P_List.Add(new ProductClass { P_ID = 1011, P_Category = "Stationery", P_Name = "Ink-Bottle", P_Cost = 45 }); P_List.Add(new ProductClass { P_ID = 1012, P_Category = "Stationery", P_Name = "NoteBooks", P_Cost = 75 }); Console.WriteLine("nLINQ WHERE"); Console.WriteLine("nProduct IDtProduct Name n"); foreach (var res in result_where) { Console.WriteLine("n"+res.P_ID+"tt"+res.P_Name); } Console.ReadKey(); } } }

Output:

Conclusion

In this article, we have seen LINQ Where which is used to retrieve a collection of elements based on a given condition. By using the where method we can limit the records easily based on several criteria.