Better Linq with better example - 1

Here in this example we take an example of 2 companies with many employees and learn how to fetch data from multilevel list (list within list) or multilevel classes( class within a class) using LINQ.

In the following example i have tried to cover all the things that can be explained using a company example.

Just copy and paste the following console application.

using System;
using System.Collections.Generic;
using System.Linq;

namespace ITCompany
{
 class Program
 {
     static void Main(string[] args)
     {
         //Create a list of Employees
         List LEmp1 = new List();
         LEmp1.Add(new Employee() { Name = "Emp01", Age = 24, salary = 40000,  Address = new Address() { PinCode = 123451,  City = "Bangalore" }});
         LEmp1.Add(new Employee() { Name = "Emp02", Age = 25, salary = 35000, Address = new Address() { PinCode = 123452, City = "Delhi" } });
         LEmp1.Add(new Employee() { Name = "Emp03", Age = 24, salary = 22000, Address = new Address() { PinCode = 123453, City = "Bombay" } });
         LEmp1.Add(new Employee() { Name = "Emp04", Age = 25, salary = 14000, Address = new Address() { PinCode = 123454, City = "Chennai" } });
         LEmp1.Add(new Employee() { Name = "Emp05", Age = 26, salary = 25000, Address = new Address() { PinCode = 123455, City = "Bangalore" } });

         Company cmp1 = new Company() { Name = "Relyon", ListEmp = LEmp1};

         List LEmp2 = new List();
         LEmp2.Add(new Employee() { Name = "Emp07", Age = 25, salary = 35000, Address = new Address() { PinCode = 123456, City = "Bangalore" } });
         LEmp2.Add(new Employee() { Name = "Emp08", Age = 24, salary = 15000, Address = new Address() { PinCode = 123457, City = "Bombay" } });
         LEmp2.Add(new Employee() { Name = "Emp09", Age = 25, salary = 10000, Address = new Address() { PinCode = 123458, City = "Delhi" } });
         LEmp2.Add(new Employee() { Name = "Emp10", Age = 26, salary = 25000, Address = new Address() { PinCode = 123459, City = "Bangalore" } });

         Company cmp2 = new Company() { Name = "CellOn" , ListEmp = LEmp2};

         Company[] ListCompany = { cmp1, cmp2 };

         //
         //Employee Details
         //
         Console.WriteLine("--------------------------------------------------------------------");
         Console.WriteLine("Employee Details");
         Console.WriteLine("--------------------------------------------------------------------");
         Console.WriteLine("Company  |       Name         |   Age |   Salary  |   Address     |");
         Console.WriteLine("--------------------------------------------------------------------");

         var EmpDetails = from comp in ListCompany
                          select new
                          {
                              Emp = (from emp in comp.ListEmp
                                     select new { Company = comp.Name, emp })
                          };

         foreach (var t in EmpDetails)
         {
             Console.WriteLine(string.Join("\n", t.Emp.Select(emp => emp.Company + "   |" + emp.emp.Name + "               |" + emp.emp.Age + "     |" + emp.emp.salary + "      |" + emp.emp.Address.City + "-" + emp.emp.Address.PinCode).ToArray()));
         }

         Console.WriteLine();
         Console.WriteLine();

         //
         //company with Employee count
         //
         Console.WriteLine("--------------------------------------------------");
         Console.WriteLine("Nos of employees");
         Console.WriteLine("--------------------------------------------------");

         var LessEmp = from Comp in ListCompany
                       select new
                       {
                           Comp.Name,
                           EmpCount = Comp.ListEmp.Count
                       };

         foreach(var t in LessEmp)
         {
             Console.WriteLine("Company Name : " + t.Name + ", Nos Of Employees : " + t.EmpCount);
         }
         Console.WriteLine(); Console.WriteLine();

         //
         //Employees who are staying in BANGALORE
         //
         Console.WriteLine("--------------------------------------------------");
         Console.WriteLine("Employees statying in bangalore");
         Console.WriteLine("--------------------------------------------------");

         var EmpInACity = from comp in ListCompany
                          from emplist in comp.ListEmp
                          where emplist.Address.City.ToUpper().Contains("BAN")
                          select new { CompName = comp.Name, EmployeeName = emplist.Name };

         foreach (var t in EmpInACity)
         {
             Console.WriteLine("Company Name : " + t.CompName + ",   Employee Name : " + t.EmployeeName);
         }
         Console.WriteLine(); Console.WriteLine();

         //
         //Employee with Hightest salary in each company
         //
         Console.WriteLine("--------------------------------------------------");
         Console.WriteLine("Highest paid employee in each company");
         Console.WriteLine("--------------------------------------------------");

         var EmpHighSalEachComp = from comp in ListCompany
                                  from empHigh in comp.ListEmp
                                  where empHigh.salary == comp.ListEmp.Max(HighEmp => HighEmp.salary)
                                  select new { CompanyName = comp.Name, EmpHighName = empHigh.Name, EmpHighSal = empHigh.salary};

         foreach (var t in EmpHighSalEachComp)
         {
             Console.WriteLine("Company : " + t.CompanyName + ", Employee : " + t.EmpHighName + ", Salary : " + t.EmpHighSal);
         }
         Console.WriteLine(); Console.WriteLine();

         //
         //Employee with Hightest salary
         //
         Console.WriteLine("--------------------------------------------------");
         Console.WriteLine("Highest paid employee from all companies");
         Console.WriteLine("--------------------------------------------------");

         var EmpHighSal = from comp in ListCompany
                          from emp in comp.ListEmp
                          where emp.salary == ListCompany.Max(TComp => TComp.ListEmp.Max(HighEmp => HighEmp.salary))
                          select new { CompanyName = comp.Name , EmployeeName = emp.Name, EmpSal = emp.salary};

         foreach (var t in EmpHighSal)
         {
             Console.WriteLine("Company : " + t.CompanyName + ", Employee : " + t.EmployeeName + ", Salary : " + t.EmpSal);
         }
         Console.WriteLine(); Console.WriteLine();

         //
         //Salary Paid in Each City together by all companies
         //
         Console.WriteLine("--------------------------------------------------");
         Console.WriteLine("Payment done in cities together by all companies");
         Console.WriteLine("--------------------------------------------------");

         var CompanyCityWise = from comp in ListCompany
                               from emp in comp.ListEmp
                               group emp by emp.Address.City into CityWiseEmp
                               select new { State = CityWiseEmp.Key, TotalSalary = CityWiseEmp.Sum(emp => emp.salary) };

         foreach (var t in CompanyCityWise)
         {
             Console.WriteLine("City : " + t.State + ",    " + "Total Salary : " + t.TotalSalary);
         }
         Console.WriteLine(); Console.WriteLine();

         //
         //Salary Paid in Each City by each company
         //
         Console.WriteLine("--------------------------------------------------");
         Console.WriteLine("Payment done in cities by each company");
         Console.WriteLine("--------------------------------------------------");

         var CityWiseSalary = from comp in ListCompany
                              select new
                              {
                                  comp.Name,
                                  Emp =(
                                      from emp in comp.ListEmp
                                      group emp by emp.Address.City into CityWiseEmp
                                      select new { State = CityWiseEmp.Key, TotalSalary = CityWiseEmp.Sum(emp => emp.salary) })
                              };

         foreach (var t in CityWiseSalary)
         {
             //t.emp comes as a structure so to easy the printing
             //we will use string.join to join all the values in a single string
             //It can also be done by looping through t.emp and
             //printing t.emp.state and t.emp.totalsalary separately

             Console.WriteLine("company : " + t.Name + "\n" + string.Join("\n", t.Emp.Select(emp => emp.State + " : " + emp.TotalSalary).ToArray()));
             Console.WriteLine(); Console.WriteLine();
         }
         Console.WriteLine(); Console.WriteLine();

     
         Console.Read();
     }
 }

 public class Company
 {
     public string Name
     { get; set; }
  
     public List ListEmp
     { get; set; }
 }

 public class Employee
 {
     public string Name
     { get; set; }

     public Address Address
     { get; set; }

     public int Age
     { get; set; }

     public double salary
     { get; set; }
 }

 public struct Address
 {
     public int PinCode
     { get; set; }
     public string City
     { get; set; }
 }
}

Output of the above program:



If any suggestions for improving the access or improving the class are always open.

If you need example on any specific topic you can leave a comment and it will be included in the coming posts.

Keep Learning. :)