The SeparateChainingHashST class represents a symbol table of generic key-value pairs. It supports the usual Put, Get, Contains, Delete, Count, and IsEmpty methods. It also provides a Keys method for iterating over all of the keys. A symbol table implements the Associative array abstraction: when associating a value with a key that is already in the symbol table, the convention is to replace the old value with the new value. Unlike DictionaryTKey, TValue, this class uses the convention that values cannot be null. Setting the value associated with a key to null is equivalent to deleting the key from the symbol table.

This implementation uses a separate chaining hash table. It requires that the key type overrides the Equals() and GetHashCode() methods. The expected time per Put, Contains, or Remove operation is constant, subject to the uniform hashing assumption. The Count, and IsEmpty operations take constant time. Construction takes constant time.