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// Order all the cars by PetName.

var subset = from c in myCars orderby c.PetName select c;

Console.WriteLine("Ordered by PetName:");

foreach (Car c in subset)

{

Console.WriteLine(c.ToString());

}

// Now find the cars that are going less than 55 mph,

// and order by descending PetName

subset = from c in myCars

where c.Speed > 55 orderby  c.PetName descending select c;

Console.WriteLine("\nCars going faster than 55, ordered by PetName:");

foreach (Car c in subset)

{

C H A P T E R   1 4  

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A N   I N T R O D U C T I O N  TO   L I N Q

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Console.WriteLine(c.ToString());

}

}

Although ascending order is the default, you are able to make your intentions very clear by

making use of the ascending operator:

var subset = from c in myCars

orderby c.PetName ascending select c;

Given these examples, you can now understand the format of a basic sorting query expression

as follows:

var result = from item in container orderby value

ascending/descending select item;

Finding Differences

The last LINQ query we will examine for the time being involves obtaining a result set that deter-

mines the differences between two IEnumerable compatible containers. Consider the following

method, which makes use of the Enumerable.Except() method to yield (in this example) a Yugo:

static void GetDiff()

{

List myCars = new List

{ "Yugo", "Aztec", "BMW"};

List yourCars = new List

{ "BMW", "Saab", "Aztec" };

var carDiff =(from c in myCars select c)

.Except(from c2 in yourCars select c2);

Console.WriteLine("Here is what you don't have, but I do:");

foreach (string s in carDiff)

Console.WriteLine(s);  // Prints Yugo.

}

These examples should give you enough knowledge to feel comfortable with the process of

building LINQ query expressions. Chapter 24 will explore the related topics of LINQ to ADO (which

is a catch-all term describing LINQ to SQL and LINQ to DataSet) and LINQ to XML. However, before

wrapping the current chapter, let’s examine the topic LINQ queries as method return values.