More Fun with LINQ Technology

This blog is based on the article written by Mahesh Chand on using LINQ to filter sets of integers. After reading Mahesh's article, I decided to have a little fun with LINQ myself.

Say we start with the following set of integers:

static int[] intArray = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 };

What if we want all the odd numbers in this set using LINQ? We can use the mod function to filter out the set we are interested in.

static void OddNumbers()
{
var oddNumberResult = from number in intArray where number % 2
== 1 select number;
Console.WriteLine("The odd numbers from 1-25: ");
Console.WriteLine("=====================");
foreach (var result in oddNumberResult)
{
Console.WriteLine(result);
}

Console.WriteLine("======================");
Console.ReadLine();
}

Let's turn it up a notch. What if we want all the perfect squares? We can use the square root in combination with rounding to figure out if a number in the set is a perfect square:

static void PerfectSquares()
{
var perfectSquaresResult = from number in intArray where
(int)(Math.Sqrt((double)number)*10) == ((int)(Math.Sqrt((double)
number)))*10 select number;

Console.WriteLine("The Perfect Squares of numbers from 1-25: ");
Console.WriteLine("=====================");
foreach (var result in perfectSquaresResult)
{
Console.WriteLine(result);
}

Console.WriteLine("======================");
Console.ReadLine();
}

One of the many real powers of LINQ is the ability to act on more than one set of numbers. Let's take the following set of arrays.

static int[] intArray2 = { 1, 2, 3, 11, 13 };
static int[] intArray3 = { 1, 2, 5, 12, 13 };

What if we wanted to find all of the common numbers between the two sets? We can use the join command to allow us to filter common numbers in both sets.

static void CommonNumbers()
{
var commonNumberResults = from number in intArray2 join number2
in intArray3 on number equals number2 select number;
Console.WriteLine("The Common Numbers between intArray2 and
intArray3: ");
Console.WriteLine("=====================");
foreach (var result in commonNumberResults)
{
Console.WriteLine(result);
}

Console.WriteLine("======================");
Console.ReadLine();
}

What if we want only the odd numbers common to both sets? Just add a where clause:

static void CommonOddNumbers()
{
var commonNumberResults = from number in intArray2 join number2
in intArray3 on number equals number2 where number % 2 == 1
select number;

Console.WriteLine("The Common Odd Numbers between intArray2 and
intArray3: ");

Console.WriteLine("=====================");

foreach (var result in commonNumberResults)
{
Console.WriteLine(result);
}

Console.WriteLine("======================");
Console.ReadLine();
}

Stay tuned for more fun with LINQ technology in C#.