public static void StudentExtensionTest()
{
Student[] studentArray =
{
new Student()
{
StudentID = 1, StudentName = "John", Age = 18
},
new Student()
{
StudentID = 2, StudentName = "Steve", Age = 21
},
new Student()
{
StudentID = 3, StudentName = "Bill", Age = 25
},
new Student()
{
StudentID = 4, StudentName = "Ram", Age = 20
},
new Student()
{
StudentID = 5, StudentName = "Ron", Age = 31
},
new Student()
{
StudentID = 6, StudentName = "Chris", Age = 17
},
new Student()
{
StudentID = 7, StudentName = "Rob", Age = 19
},
};
var students = StudentExtension.FindStudents(studentArray, delegate(Student std)
{
return(std.Age > 12 && std.Age < 20);
});
foreach (var std in students)
{
if (std != null && !string.IsNullOrEmpty(std.StudentName))
{
Console.WriteLine(std.StudentName);
}
}
//Also, use another criteria using same delegate
students = StudentExtension.FindStudents(studentArray, delegate(Student std) {
return(std.StudentID == 5);
});
}
static void Main(string[] args)
{
Console.WriteLine("LINQ Query to Array");
// Data source
string[] names = { "Bill", "Steve", "James", "Mohan" };
// LINQ Query
var myLinqQuery = from name in names
where name.Contains('a')
select name;
// Query execution
foreach (var name in myLinqQuery)
{
Console.WriteLine(name + " ");
}
Student[] studentArray =
{
new Student()
{
StudentID = 1, StudentName = "John", Age = 18
},
new Student()
{
StudentID = 2, StudentName = "Steve", Age = 21
},
new Student()
{
StudentID = 3, StudentName = "Bill", Age = 25
},
new Student()
{
StudentID = 4, StudentName = "Ram", Age = 20
},
new Student()
{
StudentID = 5, StudentName = "Ron", Age = 31
},
new Student()
{
StudentID = 6, StudentName = "Chris", Age = 17
},
new Student()
{
StudentID = 7, StudentName = "Rob", Age = 19
},
};
Student[] students = StudentExtension.Where(studentArray, delegate(Student std) {
return(std.Age > 12 && std.Age < 20);
});
// Use LINQ to find teenager students
Student[] teenAgerStudents = studentArray.Where(s => s.Age > 12 && s.Age < 20).ToArray();
// Use LINQ to find first student whose name is Bill
Student bill = studentArray.Where(s => s.StudentName == "Bill").FirstOrDefault();
// Use LINQ to find student whose StudentID is 5
Student student5 = studentArray.Where(s => s.StudentID == 5).FirstOrDefault();
Console.WriteLine("LINQ Query Syntax, example 1:");
// string collection
IList <string> stringList = new List <string>()
{
"C# Tutorials",
"VB.NET Tutorials",
"Learn C#",
"MVC Tutorials",
"Java"
};
// LINQ Query Syntax
var result = from s in stringList
where s.Contains("Tutorials")
select s;
foreach (var str in result)
{
Console.WriteLine(str);
}
Console.WriteLine("LINQ Query Syntax, example 2:");
IList <Student> studentList = new List <Student>()
{
new Student()
{
StudentID = 1, StudentName = "John", Age = 13
},
new Student()
{
StudentID = 2, StudentName = "Moin", Age = 21
},
new Student()
{
StudentID = 3, StudentName = "Bill", Age = 18
},
new Student()
{
StudentID = 4, StudentName = "Ram", Age = 20
},
new Student()
{
StudentID = 5, StudentName = "Ron", Age = 15
}
};
var teenAgerStudent = from s in studentList
where s.Age > 12 && s.Age < 20
select s;
Console.WriteLine("Teen age Students:");
foreach (Student std in teenAgerStudent)
{
Console.WriteLine(std.StudentName);
}
Console.ReadKey();
}
static void Main(string[] args)
{
List <Students> studentArray = new List <Students> {
new Students()
{
StudentID = 1, StudentName = "John", Age = 18
},
new Students()
{
StudentID = 2, StudentName = "Steve", Age = 21
},
new Students()
{
StudentID = 3, StudentName = "Bill", Age = 25
},
new Students()
{
StudentID = 4, StudentName = "Ram", Age = 20
},
new Students()
{
StudentID = 5, StudentName = "Ron", Age = 21
},
new Students()
{
StudentID = 6, StudentName = "Chris", Age = 17
},
new Students()
{
StudentID = 7, StudentName = "Rob", Age = 18
},
new Students()
{
StudentID = 8, StudentName = "John", Age = 22
},
new Students()
{
StudentID = 9, StudentName = "Ram", Age = 55
},
};
//using delegate as parameter
List <Students> st = StudentExtension.where (studentArray, delegate(Students std) {
return(std.Age > 12 && std.Age < 20);
});
foreach (var item in st)
{
if (item != null)
{
Console.WriteLine(item.StudentName);
}
}
//same result using lambda expression
var result = studentArray.Select(a => a).Where(a => a.Age > 12 && a.Age < 20);
PrintCollection(result);
//operator ofType
var stringResult = studentArray.OfType <string>();
Console.WriteLine("-----------OrderBy, ThenBy (ascending, descending)-----------");
//OrderBy, ThenBy (ascending, descending). Sort first Name i ascendig then sort by Age
var orderThenBy = studentArray.OrderBy(x => x.StudentName).ThenByDescending(x => x.Age);
Console.WriteLine("OrderBy, ThenBy (ascending, descending)");
PrintCollection(orderThenBy);
Console.WriteLine("-----------Group by-----------");
//GroupBy na Lookup
//only difference is GroupBy execution is deferred, whereas ToLookup execution is immediate
GroupByLookUp grb = new GroupByLookUp();
grb.GroupByAge(studentArray);
grb.LookUp(studentArray);
Console.WriteLine("-----------Join-----------");
//Join outer and inner collection
JoinStudents joins = new JoinStudents();
List <Courses> course = new List <Courses>()
{
new Courses()
{
CourseName = "C#", ID = 1
},
new Courses()
{
CourseName = "Java", ID = 2
},
new Courses()
{
CourseName = "Perl", ID = 3
},
new Courses()
{
CourseName = "Cplqs_plqs", ID = 4
},
};
joins.Joins(studentArray, course);
Console.WriteLine("-----------GroupJoin-----------");
GroupJoin groupJoinObject = new GroupJoin();
groupJoinObject.GroupJopinInTwoCollection(studentArray);
//more example
groupJoinObject.SpeakLang();
Console.WriteLine("-----------Aggregate-----------");
List <string> ls = new List <string>()
{
"one", "two", "three", "four"
};
string aggregate = ls.Aggregate((str1, str2) => str1 + "," + str2);
Console.WriteLine(aggregate);
Console.WriteLine("-----------Extension method: Except-----------");
OperatorExcept excObj = new OperatorExcept();
var excResult = excObj.groupOneOfStudents.Except(excObj.groupTwoOfStudents, new OperatorExcept.StudentComparer());
foreach (var item in excResult)
{
Console.WriteLine(item.StudentName);
}
Console.WriteLine("-----------Extension method: Skip/SkipWhile/Take/TakeWhile-----------");
int[] arrs = { 5, 1, 3, 22, 30, 60, 44, 55, 59, 38 };
var numbers = arrs.OrderBy(i => i).
SkipWhile(i => i < 30).
TakeWhile(i => i < 60);
foreach (var number in numbers)
{
Console.Write(number + " ");
}
Console.WriteLine("-----------Extension method: ToDictionary-----------");
List <Students> studentsToDict = new List <Students>()
{
new Students()
{
StudentID = 1, StudentName = "Peshko", Age = 3
},
new Students()
{
StudentID = 2, StudentName = "Goshklo", Age = 4
},
new Students()
{
StudentID = 3, StudentName = "Penio", Age = 5
},
new Students()
{
StudentID = 4, StudentName = "Vladko", Age = 6
},
new Students()
{
StudentID = 5, StudentName = "Bai ivan", Age = 1
}
};
var toDictionary = studentsToDict.ToDictionary <Students, int>(x => x.Age);
List <string> list = new List <string>()
{
"cat",
"dog",
"animal"
};
var animals = list.ToDictionary(x => x, x => true);
if (animals.ContainsKey("dog"))
{
// This is in the Dictionary.
Console.WriteLine("dog exists");
}
}
