- More types - TList is only a list, so is painful to use
as a lookup table and requires sequential trawling. Other languages use maps or
dictionaries that quickly find data in in-memory, lookup tables via an
identifying or key value. This is achieved with collections implementing
IMap, though IIntegerMap and IStringMap are more commonly
used for lookup by integer or string. As well as lists as IList,
developers using Smalltalk or C++ will be familiar with sets and bags
(multisets) as ISet and IBag.
- Garbage collection - unreferenced objects are automatically
destroyed, thus releasing developers from considering every possible scenario
where an object may be dropped. Collections accept ICollectable
references, thus using interface reference counting to track objects. Objects
that do not implement ICollectable can be adapted using classes such as
TObjectWrapper. Collections themselves are usually referenced using
interface references and, thus, are automatically destroyed when they are out
- Search by item value, not object reference - two, different
items can be treated as equal according to its native value (see What are
natural collections, items and keys? in downloadable help file) or using
user-written comparators. This is useful for sets or maps.
- Function versions for single items, collections and array -
operations such as adding, detecting or removing can use multiple-item
collections and arrays as well as single items.
- Filter functions - particular items can be extracted according
to user-written filter classes or functions. This can be achieved by the
Find(Filter), FindAll and GetIterator(Filter) functions,
- List sort order is maintained - once a list is set as sorted,
Add(Item) functions inserts the item into the correct place.
- Cloning - Clone creates a shallow copy of a collection.