101 LINQ Samples: Conversion Operators

ToArray

This sample uses ToArray to immediately evaluate a sequence into an array.

     
       
 
        
public void Linq54()
 
        
{
 
        
    double[] doubles = { 1.7, 2.3, 1.9, 4.1, 2.9 };
 
        
 
 
        
    var sortedDoubles =
 
        
        from d in doubles
 
        
        orderby d descending
 
        
        select d;
 
        
    var doublesArray = sortedDoubles.ToArray();
 
        
 
 
        
    Console.WriteLine("Every other double from highest to lowest:");
 
        
    for (int d = 0; d < doublesArray.Length; d += 2)
 
        
    {
 
        
        Console.WriteLine(doublesArray[d]);
 
        
    }
 
        
}
 
       

Result

Every other double from highest to lowest:
4.1
2.3
1.7

ToList

This sample uses ToList to immediately evaluate a sequence into a List<T>.

     
       
 
        
public void Linq55()
 
        
{
 
        
    string[] words = { "cherry", "apple", "blueberry" };
 
        
 
 
        
    var sortedWords =
 
        
        from w in words
 
        
        orderby w
 
        
        select w;
 
        
    var wordList = sortedWords.ToList();
 
        
 
 
        
    Console.WriteLine("The sorted word list:");
 
        
    foreach (var w in wordList)
 
        
    {
 
        
        Console.WriteLine(w);
 
        
    }
 
        
}
 
       

Result

The sorted word list:
apple
blueberry
cherry

ToDictionary

This sample uses ToDictionary to immediately evaluate a sequence and a related key expression into a dictionary.

     
       
 
        
public void Linq56()
 
        
{
 
        
    var scoreRecords = new[] { new {Name = "Alice", Score = 50},
 
        
                                new {Name = "Bob"  , Score = 40},
 
        
                                new {Name = "Cathy", Score = 45}
 
        
                            };
 
        
 
 
        
    var scoreRecordsDict = scoreRecords.ToDictionary(sr => sr.Name);
 
        
 
 
        
    Console.WriteLine("Bob's score: {0}", scoreRecordsDict["Bob"]);
 
        
}
 
       

Result

Bob's score: { Name = Bob, Score = 40 }

OfType

This sample uses OfType to return only the elements of the array that are of type double.

     
       
 
        
public void Linq57()
 
        
{
 
        
    object[] numbers = { null, 1.0, "two", 3, "four", 5, "six", 7.0 };
 
        
 
 
        
    var doubles = numbers.OfType<double>();
 
        
 
 
        
    Console.WriteLine("Numbers stored as doubles:");
 
        
    foreach (var d in doubles)
 
        
    {
 
        
        Console.WriteLine(d);
 
        
    }
 
        
}
 
       

Result

Numbers stored as doubles:
1
7