I am looking for a very fast way to filter down a collection in C#. I am currently using generic List<object> collections, but am open to using other structures if they perform better.
Currently, I am just creating a new List<object> and looping thru the original list. If the filtering criteria matches, I put a copy into the new list.
Is there a better way to do this? Is there a way to filter in place so there is no temporary list required?
You can use IEnumerable to eliminate the need of a temp list.
public IEnumerable<T> GetFilteredItems(IEnumerable<T> collection)
{
foreach (T item in collection)
if (Matches<T>(item))
{
yield return item;
}
}
where Matches is the name of your filter method. And you can use this like:
IEnumerable<MyType> filteredItems = GetFilteredItems(myList);
foreach (MyType item in filteredItems)
{
// do sth with your filtered items
}
This will call GetFilteredItems function when needed and in some cases that you do not use all items in the filtered collection, it may provide some good performance gain.