LINQ examples
C# Lambda Expressions
Code:
string[] names = { "Kisan", "Devang", "Ravi", "Ujas", "Karan" };
IEnumerable query = names
.Where(n => n.Contains("n"))
.Select(n => n.ToUpper());
foreach (var name in query)
Console.WriteLine(name);
Console.WriteLine("Press any key to continue
...");
Console.ReadLine();
Result
LINQ Filtering
Operator
Code:
string[] names = { "Kisan", "Ravi", "Ujas", "Karan", "Ketul" };
Console.WriteLine("Name start with K:");
IEnumerable query1 = names.Where(name =>
name.StartsWith("K"));
foreach (string name in query1)
{
Console.WriteLine(name);
}
Console.WriteLine("Name end with n: ");
IEnumerable query2 = from n in names where n.EndsWith("n") select n;
foreach (string name in query2)
{
Console.WriteLine(name);
}
Console.WriteLine("Press any key to continue
...");
Console.ReadLine();
Result
LINQ “let” Operator
Code:
class Program
{
static void Main(string[] args)
{
List<Person>
persons = new List<Person>{
new Person{ Name = "Kisan", City="Ladol" },
new Person{ Name = "Ravi", City = "Ladol" },
new Person{ Name = "Ketul", City = "Vijapur" },
new Person{ Name = "Kisan", City = "Vijapur" },
};
var query = from p in persons
let lname = p.Name.ToLower()
where lname == "kisan"
select new { lname, p.City };
foreach (var name in query)
Console.WriteLine(name.lname + " - " + name.City);
Console.WriteLine("Press any key to
continue!!!");
Console.ReadLine();
}
}
public class Person
{
public string Name { get; set; }
public string City { get; set; }
}
Result
LINQ Queries “into”
Keyword
Code:
class Program
{
static void Main(string[] args)
{
List<Person>
persons = new List<Person>{
new Person{ Name = "Kisan", City="Ladol" },
new Person{ Name = "Ravi", City = "Ladol" },
new Person{ Name = "Kate", City = "Vijapur" },
new Person{ Name = "Kisan", City = "Vijapur" },
};
var query = from p in persons
where p.Name.StartsWith("K")
select p
into pNames
where pNames.Name.Length > 4
select pNames;
foreach (var name in query)
Console.WriteLine(name.Name + " - " + name.City);
Console.WriteLine("Press any key to
continue!!!");
Console.ReadLine();
}
}
public class Person
{
public string Name { get; set; }
public string City { get; set; }
}
Result
LINQ Grouping Operator
Code:
class Program
{
static void Main(string[] args)
{
List<Customer>
customers = new List<Customer>{
new Customer{ Id = 1, Name = "Kisan", City="Ladol" },
new Customer{ Id = 2, Name = "Kite", City = "Ladol" },
new Customer{ Id = 3, Name = "Ketul", City = "Vijapur" },
new Customer{ Id = 4, Name = "Kisan", City = "Vijapur" },
};
var query = from c in customers
group c by c.City;
foreach (var group in query)
{
Console.WriteLine("Group City : " + group.Key);
foreach (var name in group)
{
Console.WriteLine(name.Id + " - " + name.Name);
}
}
Console.WriteLine("Press any key to
continue!!!");
Console.ReadLine();
}
}
public class Customer
{
public int Id { get; set; }
public string Name { get; set; }
public string City { get; set; }
}
Result
LINQ order by Operator
Code:
class Program
{
static void Main(string[] args)
{
List<Customer>
customers = new List<Customer>{
new Customer{ Id = 1, Name = "Peter", City="Ladol" },
new Customer{ Id = 2, Name = "Kite", City = "Ladol" },
new Customer{ Id = 3, Name = "Ketul", City = "Vijapur" },
new Customer{ Id = 4, Name = "Marry", City = "Vijapur" },
};
var query = from c in customers
orderby c.Name
group c by c.City;
foreach (var group in query)
{
Console.WriteLine("Group City : " + group.Key);
foreach (var name in group)
{
Console.WriteLine(name.Id + " - " + name.Name);
}
}
Console.WriteLine("Press any key to
continue!!!");
Console.ReadLine();
}
}
public class Customer
{
public int Id { get; set; }
public string Name { get; set; }
public string City { get; set; }
}
Result
LINQ Quantifier
Operators : “All” and “Contains”
Code:
class Program
{
static void Main(string[] args)
{
//LINQ Quantifier Operators :
“Any”, “All” and “Contains”
List<Customer>
customers = new List<Customer>{
new Customer{ Id = 1, Name = "Peter", City="Ladol" },
new Customer{ Id = 2, Name = "Kite", City = "Ladol" },
new Customer{ Id = 3, Name = "Ketul", City = "Vijapur" },
new Customer{ Id = 4, Name = "Marry", City = "Vijapur" },
};
bool query = customers.All(c => c.Name.ToLower().Contains("p"));
if (query)
{
Console.WriteLine("Existing all customer with
name contains p");
}
else
{
Console.WriteLine("not existing all customer
with name contains p. just have Peter");
}
Console.WriteLine("Press any key to
continue!!!");
Console.ReadLine();
}
}
public class Customer
{
public int Id { get; set; }
public string Name { get; set; }
public string City { get; set; }
}
Result
LINQ Quantifier
Operators : “All” and “Contains”
Code:
class Program
{
static void Main(string[] args)
{
//LINQ Quantifier Operators :
“Any”, “All” and “Contains”
List<Customer>
customers = new List<Customer>{
new Customer{ Id = 1, Name = "Peter", City="Ladol" },
new Customer{ Id = 2, Name = "Kite", City = "Ladol" },
new Customer{ Id = 3, Name = "Ketul", City = "Vijapur" },
new Customer{ Id = 4, Name = "Marry", City = "Vijapur" },
};
bool query = customers.Any(c => c.Name.ToLower().Contains("P"));
if (query)
{
Console.WriteLine("Existing all customer with
name contains p");
}
else
{
Console.WriteLine("not existing all customer
with name contains p. just have Peter");
}
Console.WriteLine("Press any key to
continue!!!");
Console.ReadLine();
}
}
public class Customer
{
public int Id { get; set; }
public string Name { get; set; }
public string City { get; set; }
}
Result
LINQ Take Operators
Code:
class Program
{
static void Main(string[] args)
{
//LINQ Take Operators
List<Customer>
customers = new List<Customer>{
new Customer{ Id = 1, Name = "Peter", City="Ladol" },
new Customer{ Id = 2, Name = "Kite", City = "Ladol" },
new Customer{ Id = 3, Name = "Ketul", City = "Vijapur" },
new Customer{ Id = 4, Name = "Marry", City = "Vijapur" },
};
var customer = customers.Take(3);
foreach (var c in customer)
{
Console.WriteLine(c.Name);
}
Console.WriteLine("Press any key to
continue!!!");
Console.ReadLine();
}
}
public class Customer
{
public int Id { get; set; }
public string Name { get; set; }
public string City { get; set; }
}
Result
LINQ Skip Operators
Code:
class Program
{
static void Main(string[] args)
{
//LINQ Take Operators
List<Customer>
customers = new List<Customer>{
new Customer{ Id = 1, Name = "Peter", City="Ladol" },
new Customer{ Id = 2, Name = "Kite", City = "Ladol" },
new Customer{ Id = 3, Name = "Ketul", City = "Vijapur" },
new Customer{ Id = 4, Name = "Marry", City = "Vijapur" },
};
var customer = customers.Skip(2);
foreach (var c in customer)
{
Console.WriteLine(c.Name);
}
Console.WriteLine("Press any key to
continue!!!");
Console.ReadLine();
}
}
public class Customer
{
public int Id { get; set; }
public string Name { get; set; }
public string City { get; set; }
}
Result
LINQ Partitioning
Operators – “Take” and “Skip”
Code:
class Program
{
static void Main(string[] args)
{
//LINQ Take Operators
List<Customer>
customers = new List<Customer>{
new Customer{ Id = 1, Name = "Peter", City="Ladol" },
new Customer{ Id = 2, Name = "Kite", City = "Ladol" },
new Customer{ Id = 3, Name = "Ketul", City = "Vijapur" },
new Customer{ Id = 4, Name = "Marry", City = "Vijapur" },
};
var customer = customers.Skip(2).Take(2);
foreach (var c in customer)
{
Console.WriteLine(c.Name);
}
Console.WriteLine("Press any key to
continue!!!");
Console.ReadLine();
}
}
public class Customer
{
public int Id { get; set; }
public string Name { get; set; }
public string City { get; set; }
}
Result
LINQ Element Operators
Code:
class Program
{
static void Main(string[] args)
{
//LINQ Take Operators
List<Customer>
customers = new List<Customer>{
new Customer{ Id = 1, Name = "Peter", City="Ladol" },
new Customer{ Id = 2, Name = "Pite", City = "Ladol" },
new Customer{ Id = 3, Name = "Ketul", City = "Vijapur" },
new Customer{ Id = 4, Name = "Marry", City = "Vijapur" },
};
var customer = (from c in customers where c.Name.Contains("P") select new { c.Id,
c.Name,c.City}).FirstOrDefault();
Console.WriteLine("Name: " + customer.Name);
Console.WriteLine("Press any key to
continue!!!");
Console.ReadLine();
}
}
public class Customer
{
public int Id { get; set; }
public string Name { get; set; }
public string City { get; set; }
}
Result
Done!!!
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