/*public static IEnumerable<IGrouping<K, T>> GroupBy<T, K, E>(
* this IEnumerable<T> source,
* Func<T, K> keySelector,
* Func<T, E> elementSelector.
* IEqualityComparer<K> comparer);
* */
void GroupByOperator4th()
{
MyFounderNumberComparer comp = new MyFounderNumberComparer ();
EmployeeOptionEntry[] emOptions = EmployeeOptionEntry.GetEmployeeOptionEntries ();
IEnumerable<IGrouping<int, DateTime>> opts = emOptions
.GroupBy (key => key.id, element => element.dateAwarded, comp);
foreach (IGrouping<int, DateTime> keyGroup in opts) {
Console.WriteLine("Option dates for: " + (comp.isFounder(keyGroup.Key) ? "founder" : "nonfounder"));
foreach(DateTime date in keyGroup)
{
Console.WriteLine(date.ToShortDateString());
}
}
}
/*public static IEnumerable<IGrouping<K, T>> GroupBy<T, K>(
* this IEnumerable<T> source,
* Func<T, K> keySelector,
* IEqualityComparer<K> comparer);
* */
void GroupByOperator2nd()
{
MyFounderNumberComparer comp = new MyFounderNumberComparer();
EmployeeOptionEntry[] emOptions = EmployeeOptionEntry.GetEmployeeOptionEntries();
IEnumerable<IGrouping<int, EmployeeOptionEntry>> opts = emOptions
.GroupBy(o => o.id, comp);
//First enumerate trough the sequence of IGroupings.
foreach(IGrouping<int, EmployeeOptionEntry> keyGroup in opts)
{
Console.WriteLine("Option records for: " + (comp.isFounder(keyGroup.Key) ? "founder" :"nonfounder"));
//now enumerate trough the grouping's sequence of EmployeeOptionEntry elements.
foreach(EmployeeOptionEntry element in keyGroup)
{
Console.WriteLine("id={0} : optionsCount= {1} : dateAwarded={2:d}",
element.id, element.optionsCount, element.dateAwarded);
}
}
}