Provides a reduced view of a dataset

The SubsetView class is derived from the BaseView class and overrides the getData() method to provide for dynamically changing the appearance of the underlying dataset. This allows for datasets (which are immuatable) to appear to the user as mutable.

__extractColumns ( self,  data )

__extractRows ( self,  data )

__init__ (
        self,
        dataset,
        keyset=[],
        )

getData ( self,  key=None )

getNumCols ( self )

getNumRows ( self )