Chapter 7. Collections

Collections are standard data structures that supplement arrays, which are the only built-in data structures in C#. In this, C# differs from languages such as Perl and Python, which incorporate key/value data structures and dynamically sized arrays into the language itself.

The FCL includes a set of types that provide commonly required data structures and support for creating your own. These types are typically broken down into two categories: interfaces that define a standardized set of design patterns for collection classes in general, and concrete classes that implement these interfaces and provide a usable range of data structures.

This chapter introduces all the concrete collection classes and abstract collection interfaces and provides examples of their use. Unless otherwise stated, the types mentioned in this section all exist in the System.Collections or System.Collections.Specialized namespaces, which are both documented in the reference section of this book, Part V.