— Function: gethash key table &optional default

This function looks up key in table, and returns its associated value—or default, if key has no association in table.

— Function: puthash key value table

This function enters an association for key in table, with value value. If key already has an association in table, value replaces the old associated value.

— Function: remhash key table

This function removes the association for key from table, if there is one. If key has no association, remhash does nothing.

— Function: clrhash table

This function removes all the associations from hash table table, so that it becomes empty. This is also called clearing the hash table.

— Function: maphash function table

This function calls function once for each of the associations in table. The function function should accept two arguments—a key listed in table, and its associated value.