在 R 的 ggplot 2 中使用更多数据帧

Question

I get an error when i try to use more than one dataframe in a ggplot2; Error: mapping must be created by aes()

xdf <- data.frame(x=1:3, y=c(18,11,16))
ydf <- data.frame(x=c(5,7), y=c(18,11))

ggplot(xdf, aes(x,y))+ 
  geom_point()+
  geom_point(ydf, aes(x,y) )

Is this solvable...?

Answer 1

You need to specify that ydf is the data parameter:

ggplot(xdf, aes(x,y))+ 
  geom_point()+
  geom_point(data=ydf, aes(x,y))

Answer 2

Some additional remarks for others who need to work with different data in ggplot2 :

If you define aes globally within the function ggplot and you need the same aesthetics, you do not have to write them again.

ggplot(xdf, aes(x, y)) + 
  geom_point() +
  geom_point(data = ydf)

If you need different aesthetics, you can set inherit.aes = FALSE to ignore the global aesthetics.

ggplot(xdf, aes(x, y, color = z)) + 
  geom_point() +
  geom_point(data=ydf, aes(y, x), inherit.aes = FALSE)