Software Development

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

SequenceEqual Operator with Take and Count

Posted on by coder 
   
 

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

public class MainClass {
    public static void Main() {
        string[] presidents = {"G", "H", "a", "H", "over", "Jack"};

        bool eq = presidents.SequenceEqual(presidents.Take(presidents.Count()));
        Console.WriteLine(eq);

    }
}

SequenceEqual Operator with string array

Posted on by coder 
   
 

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
public class MyStringifiedNumberComparer : IEqualityComparer<string> {
    public bool Equals(string x, string y) {
        return (Int32.Parse(x) == Int32.Parse(y));
    }

    public int GetHashCode(string obj) {
        return Int32.Parse(obj).ToString().GetHashCode();
    }
}
public class MainClass {
    public static void Main() {
        string[] stringifiedNums1 = { "101", "49", "017", "1080", "00027", "2" };
        string[] stringifiedNums2 = {"1", "1049", "17", "080", "27", "02" };
        bool eq = stringifiedNums1.SequenceEqual(stringifiedNums2,new MyStringifiedNumberComparer());
        Console.WriteLine(eq);
    }
}

SequenceEqual Operator

Posted on by coder 
   
 

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

public class MainClass {
    public static void Main() {
        string[] presidents = {"G", "H", "a", "H", "over", "Jack"};

        bool eq = presidents.SequenceEqual(presidents);
        Console.WriteLine(eq);

    }
}

SelectMany Prototype: with ? operator

Posted on by coder

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
public class MainClass {
public static void Main() {
string[] presidents = {“A”, “Art”, “Buch”, “Bush”, “Carter”, “land”};

IEnumerable chars = presidents
.SelectMany((p, i) => i < 5 ? p.ToArray() : new char[] { }); foreach (char ch in chars) Console.WriteLine(ch); } } [/csharp]

SelectMany Prototype

Posted on by coder 
   
 

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
public class MainClass {
    public static void Main() {
        string[] presidents = {"Ad", "Art", "Buch", "Bush", "Car", "land"};

        IEnumerable<char> chars = presidents.SelectMany(p => p.ToArray());

        foreach (char ch in chars)
            Console.WriteLine(ch);

    }
}

A More Complex Example of the First SelectMany

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());
    }
}
public class EmployeeOptionEntry {
    public int id;
    public long optionsCount;
    public DateTime dateAwarded;

    public static EmployeeOptionEntry[] GetEmployeeOptionEntries() {
        EmployeeOptionEntry[] empOptions = new EmployeeOptionEntry[] {
      new EmployeeOptionEntry {
        id = 1,
        optionsCount = 2,
         dateAwarded = DateTime.Parse("1999/12/31") },
       new EmployeeOptionEntry {
        id = 101,
        optionsCount = 2,
        dateAwarded = DateTime.Parse("1998/12/31") }
    };

        return (empOptions);
    }
}


public class MainClass {
    public static void Main() {
        Employee[] employees = Employee.GetEmployeesArray();
        EmployeeOptionEntry[] empOptions = EmployeeOptionEntry.GetEmployeeOptionEntries();

        var employeeOptions = employees

         .SelectMany(e => empOptions
                               .Where(eo => eo.id == e.id)
                               .Select(eo => new {
                                   id = eo.id,
                                   optionsCount = eo.optionsCount
                               }));

        foreach (var item in employeeOptions)
            Console.WriteLine(item);

    }
}