print to pdf file using grid.table in r - too many rows to fit on one page

gridextra, pdf, r

Solution

I'd suggest the following strategy: create the tableGrob, query its heights, split the rows to fit each page,

library(gridExtra)
library(grid)
d <- iris[sample(nrow(iris), 187, TRUE),]
tg <- tableGrob(d, rows = seq_len(nrow(d))) 

fullheight <- convertHeight(sum(tg$heights), "cm", valueOnly = TRUE)
margin <- unit(0.51,"in")
margin_cm <- convertHeight(margin, "cm", valueOnly = TRUE)
a4height <- 29.7 - margin_cm
nrows <- nrow(tg)
npages <- ceiling(fullheight / a4height)

heights <- convertHeight(tg$heights, "cm", valueOnly = TRUE) 
rows <- cut(cumsum(heights), include.lowest = FALSE,
            breaks = c(0, cumsum(rep(a4height, npages))))

groups <- split(seq_len(nrows), rows)

gl <- lapply(groups, function(id) tg[id,])

pdf("multipage.pdf", paper = "a4", width = 0, height = 0)
for(page in seq_len(npages)){
  grid.newpage()
  grid.rect(width=unit(21,"cm") - margin,
            height=unit(29.7,"cm")- margin)
  grid.draw(gl[[page]])
}
## alternative to explicit loop:
## print(marrangeGrob(grobs=gl, ncol=1, nrow=1, top=NULL))
dev.off()

Problem

I'm trying to output a dataframe of about 40 rows and 5 columns to a .pdf file using grid.table in gridExtra package of R. However, 40 rows is too long for a page so the .pdf file only shows part of the dataframe. I want to know if I can print two columns on one page so all of the rows show up on one page. Alternatively, I need to know how to print the dataframe over multiple pages. Thanks, John

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