static void Main()
{
var towns = new RankedDictionary <string, int>();
// Load sample data.
towns.Add("Albany", 43600);
towns.Add("Bandon", 2960);
towns.Add("Corvallis", 54462);
towns.Add("Damascus", 10539);
towns.Add("Elkton", 195);
towns.Add("Florence", 8466);
towns.Add("Glide", 1795);
towns.Add("Jacksonville", 2235);
towns.Add("Lebanon", 13140);
towns.Add("Lookingglass", 855);
towns.Add("Medford", 75180);
towns.Add("Powers", 689);
towns.Add("Riddle", 1020);
towns.Add("Roseburg", 20480);
towns.Add("Scio", 710);
towns.Add("Talent", 6066);
towns.Add("Umatilla", 6906);
towns.Add("Winston", 5379);
towns.Add("Yamhill", 820);
// Here's a typical LINQ-To-Objects operation.
double avg = towns.Average(x => x.Value);
Console.WriteLine($"Average population of all towns = {avg:f0}");
// Lambda expression
IEnumerable <KeyValuePair <string, int> > r1 = towns.Where(t => t.Key.CompareTo("E") < 0);
Console.WriteLine("\nTowns A-D:");
foreach (KeyValuePair <string, int> e in r1)
{
Console.WriteLine(e.Key);
}
// LINQ range: O(n)
IEnumerable <KeyValuePair <string, int> > r2 = towns.SkipWhile(t => t.Key.CompareTo("E") < 0).TakeWhile(t => t.Key.CompareTo("J") < 0);
Console.WriteLine("\nTowns E-G:");
foreach (KeyValuePair <string, int> e in r2)
{
Console.WriteLine(e.Key);
}
//
// Use the ElementsBetween iterator to query range.
// Unlike LINQ SkipWhile and TakeWhile, this will perform an optimized (partial scan) lookup.
//
// BtreeDictionary range operator: O(log n)
IEnumerable <KeyValuePair <string, int> > r3 = towns.ElementsBetween("K", "M");
Console.WriteLine("\nTowns K-L:");
foreach (KeyValuePair <string, int> town in r3)
{
Console.WriteLine(town.Key);
}
// Range operator without upper limit: O(log n)
IEnumerable <KeyValuePair <string, int> > r4 = towns.ElementsFrom("M");
Console.WriteLine("\nTowns M-R:");
foreach (KeyValuePair <string, int> town in r4)
{
// This avoids the issue in the last example where a town named "M" would be included.
if (town.Key.CompareTo("S") >= 0)
{
break;
}
else
{
Console.WriteLine(town.Key);
}
}
// Range operator without upper limit: O(log n)
IEnumerable <KeyValuePair <string, int> > r5 = towns.ElementsFrom("T");
Console.WriteLine("\nTowns T-Z:");
foreach (KeyValuePair <string, int> town in r5)
{
Console.WriteLine(town.Key);
}
}