GroupBy - Simple 2

Query

public void Linq41()
{
    string[] words = { "blueberry", "chimpanzee", "abacus", "banana", "apple", "cheese" };
      
    var wordGroups =
        from w in words
        group w by w[0] into g
        select new { FirstLetter = g.Key, Words = g };
      
    foreach (var g in wordGroups)
    {
        Console.WriteLine("Words that start with the letter '{0}':", g.FirstLetter);
        foreach (var w in g.Words)
        {
            Console.WriteLine(w);
        }
    }
}

Lambda Expression

public void DataSetLinq41()
{
    var words4 = testDS.Tables["Words4"].AsEnumerable();
 
    var wordGroups = words4.GroupBy(w => w.Field("word")[0]).Select(g => new {FirstLetter = g.Key, Words = g});
 
    foreach (var g in wordGroups)
    {
        Console.WriteLine("Words that start with the letter '{0}':", g.FirstLetter);
        foreach (var w in g.Words)
        {
            Console.WriteLine(w.Field("word"));
        }
    }
}

Output

Words that start with the letter 'b':
blueberry
banana
Words that start with the letter 'c':
chimpanzee
cheese
Words that start with the letter 'a':
abacus
apple