Rpart Outcome into PDF files in R

Question

I am building some regression tree models, I have done everything, now I want to write the trees to a pdf file. I am using below command to generate it.

pdf(file=paste0("Plots1.pdf"), header= "Rpart Outcome" )
lapply(names(tree.2), function(x)fancyRpartPlot(tree.2[[x]]))
dev.off()

The tree.2 object contains 8 different models of rpart and it is saved as a list.

The above command works like a charm but the problem is that I want a separate header on top of every page of PDF as per the names of the list tree.2 (names(tree.2)), I have tried lot of different permutation and combination but unable to solve it via lapply, However if I use a for loop the above thing is achievable. I want to use lapply to perform this, Is it possible? I know it is, but I am not able to do it for now.

Libraries used here: rattle, rpart

Toy example:

tree1 <- rpart(as.formula(mpg ~ hp + wt), data=mtcars)
tree2 <- rpart(as.formula(mpg ~ am + hp), data=mtcars)
treex <- list("tree1"= tree1, "tree2"=tree2)

pdf(file="file.pdf", header="Rpart Outcome")
lapply(names(treex), function(x)fancyRpartPlot(treex[[x]]))
dev.off()

Here, I want header on every page basis names(treex).

Please let me know in case if its a duplicate question (haven't found one), I will remove immediately.

Thanks

Answer 1

This seems to work for me:

library(rpart)
  library(rattle)

  tree1 <- rpart(as.formula(mpg ~ hp + wt), data=mtcars)
  tree2 <- rpart(as.formula(mpg ~ am + hp), data=mtcars)
  treex <- list("tree1"= tree1, "tree2"=tree2)

  pdf(file="file.pdf")#, header="Rpart Outcome")
  lapply(names(treex), function(x)fancyRpartPlot(treex[[x]], main = x))
  dev.off()

I have just added an argument main in the fancyRpartPlot which takes the name of the plot.

Hope it helps!