Conversion Operators

To Array

This sample generates an array of double values by first using a query expression with orderby to create a sorted sequence of doubles, then ToArray to generate an array from the sequence.

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

To List

This sample generates an array of string values by first using a query expression with orderby to create a sorted sequence of strings from a string array, then toList to generate a List from the sequence.

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

To Dictionary

This sample uses anonymous types to create a data structure of people and their scores. It then uses ToDictionary to generate a dictionary from the sequence and its key expression.

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 prints all of the elements of an array that are of type double. The sample uses OfType to test the element's type.

public void Linq57() {
    object[] numbers = { null, 1.0, "two", 3, 4.0f, 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