@property<EOL><INDENT>def xindex(self):<DEDENT>
try:<EOL><INDENT>return self._xindex<EOL><DEDENT>except AttributeError:<EOL><INDENT>self._xindex = Index.define(self.x0, self.dx, self.shape[<NUM_LIT:0>])<EOL>return self._xindex<EOL><DEDENT>
Positions of the data on the x-axis

        :type: `~astropy.units.Quantity` array