def sorted(self, by, **kwargs):
        """Sort array by a column.

        Parameters
        ==========
        by: str
            Name of the columns to sort by(e.g. 'time').
        """
        sort_idc = np.argsort(self[by], **kwargs)
        return self.__class__(
            self[sort_idc],
            h5loc=self.h5loc,
            split_h5=self.split_h5,
            name=self.name
        )