Software Development

software development notes, main category for Cs, Java, and other programming experiences.

Use static method syntax to call the query operators.

Posted on by coder 
   
 

using System;
using System.Collections.Generic;
using System.Linq;
public class MainClass {
    public static void Main() {
        string[] names = { "J", "P", "G", "Pa" };

        IEnumerable<string> filtered = Enumerable.Where(names,n => n.Contains("a"));
        IEnumerable<string> sorted = Enumerable.OrderBy(filtered, n => n.Length);
        IEnumerable<string> finalQuery = Enumerable.Select(sorted,n => n.ToUpper());

    }
}

Calling the Range Operator

Posted on by coder 
   
 

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

public class MainClass {
    public static void Main() {
        IEnumerable<int> ints = Enumerable.Range(1, 10);
        foreach (int i in ints)
            Console.WriteLine(i);
    }
}

Use Generation Operators: Range

Posted on by coder 
   
 

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

public class MainClass {
    public static void Main() {
        var numbers =
           from n in Enumerable.Range(100, 50)
           select new { Number = n, OddEven = n % 2 == 1 ? "odd" : "even" };

        foreach (var n in numbers) {
            Console.WriteLine("The number {0} is {1}.", n.Number, n.OddEven);
        }
    }
}

Return an Empty Sequence of Strings

Posted on by coder 
   
 
using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;

public class MainClass {
    public static void Main() {
        IEnumerable<string> strings = Enumerable.Empty<string>();
        foreach (string s in strings)
            Console.WriteLine(s); Console.WriteLine(strings.Count());
    }
}

ElementAtOrDefault Operator with an Invalid Index

Posted on by coder 
   
 

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
public class Employee {
    public int id;
    public string firstName;
    public string lastName;

    public static ArrayList GetEmployeesArrayList() {
        ArrayList al = new ArrayList();
        al.Add(new Employee { id = 1, firstName = "J", lastName = "R" });
        al.Add(new Employee { id = 2, firstName = "W", lastName = "G" });
        al.Add(new Employee { id = 3, firstName = "A", lastName = "H" });
        al.Add(new Employee { id = 4, firstName = "D", lastName = "L" });
        al.Add(new Employee { id = 101, firstName = "K", lastName = "F" });
        return (al);
    }

    public static Employee[] GetEmployeesArray() {
        return ((Employee[])GetEmployeesArrayList().ToArray(typeof(Employee)));
    }
}
public class MainClass {
    public static void Main() {
        Employee emp = Employee.GetEmployeesArray().ElementAtOrDefault(5);

        Console.WriteLine(emp == null ? "NULL" : string.Format("{0} {1}", emp.firstName, emp.lastName));
    }
}