def standardize(self, axis=1):
        """
        Divide by standard deviation either within or across records.

        Parameters
        ----------
        axis : int, optional, default = 0
            Which axis to standardize along, within (1) or across (0) records
        """
        if axis == 1:
            return self.map(lambda x: x / std(x))
        elif axis == 0:
            stdval = self.std().toarray()
            return self.map(lambda x: x / stdval)
        else:
            raise Exception('Axis must be 0 or 1')