def getColumn(self, columnKey):
        """Gets or creates the column subdirectory matching key.

        Note that the "columns" returned by this method need not be complete.
        They will contain only the items corresponding to the keys that
        have actually been inserted.  Other items will not be present,
        in particular they will not be represented by None."""
        
        # Get a list of the keys to the primary dictionary
        rows = self.keys()

        # Create the empty column dictionary
        column = {}

        # Now index through the rows, retrieving the appropriate "column"
        # entries and adding them to the column
        for row in rows:
            thisRow = self.getRow(row)
            if thisRow.has_key(columnKey):
                column[row] = thisRow[columnKey]
        return column
Gets or creates the column subdirectory matching key.

        Note that the "columns" returned by this method need not be complete.
        They will contain only the items corresponding to the keys that
        have actually been inserted.  Other items will not be present,
        in particular they will not be represented by None.
recipes/Python/68430_Dictionarybased_twodimensional_ragged/recipe-68430.py