multiple left hand side columns

[ggrothendieck]

Would be nice to have the lattice feature which allows multiple columns on left hand side so that wide form data frames can be directly graphed without converting to long form.

library(lattice)

xyplot(y1 + y2  ~ x1, anscombe, col = 1:2, pch = 20, cex = 2) # plots y1 and y2 in same panel

# error but would be nice if it worked in ggformula
xyplot(. ~ x1, anscombe[c("x1", "y1", "y2")], col = 1:2, pch = 20, cex = 2) 

# unravels LHS into vector but would be better if it treated LHS as 2 columns in ggformula
xyplot(cbind(y1, y2) ~ x1, anscombe, col = 1:2, pch = 20, cex = 2) 

lm(cbind(y1, y2) ~ x1, anscombe) # regresses each of y1 and y2 on x1

This doesn't work in ggformula either:

gf_line(anscombe, c(y1, y2) ~ x1)

but can be done in lattice. Here x1 is recycled.

xyplot(c(y1, y2) ~ x1, anscombe, pch = 20, cex = 2)

[rpruim]

Since ggformula passes things to ggplot for plotting, and ggplot doesn't really support this, this might be tricky. I'll have to give this a bit of thought.

[ggrothendieck]

It would be sufficient to form the left hand side into a vector and then generate a corresponding group= aesthetic.