qplot(carat , price , data = dsmall , geom = c("point","smooth")) ##注意几何对象会根据c()的顺序进行堆叠 qplot(carat , price , data = diamonds , geom = c("smooth","point")) ##先画smooth会使其被覆盖 ##曲线平滑程度,使用参数span控制,取值0(很不平滑)~ 1(很平滑) qplot(carat , ...