dbook.R

printf <- function(...)
{
	print(sprintf(...), quote=F)
}

print.head <- function(tbl, n = 5)
{
	kable(head(tbl, n))
}

load.packages <- function(pkgs)
{
	if(class(pkgs) == "character")
		pkgs = c(pkgs)
	for(pkg in pkgs){
		if(!(pkg %in% installed.packages()[,"Package"])){
			printf("installing %s", pkg)
			install.packages(pkg, repos="http://cran.us.r-project.org")
		}
		library(pkg,character.only=TRUE)
		printf("loading %s", pkg)
	}
}

multiplot <- function(..., plotlist=NULL, file, cols=1, layout=NULL) {
	library(grid)
	
	# Make a list from the ... arguments and plotlist
	plots <- c(list(...), plotlist)
	
	numPlots = length(plots)
	
	# If layout is NULL, then use 'cols' to determine layout
	if (is.null(layout)) {
		# Make the panel
		# ncol: Number of columns of plots
		# nrow: Number of rows needed, calculated from # of cols
		layout <- matrix(seq(1, cols * ceiling(numPlots/cols)),
						 ncol = cols, nrow = ceiling(numPlots/cols))
	}
	
	if (numPlots==1) {
		print(plots[[1]])
		
	} else {
		# Set up the page
		grid.newpage()
		pushViewport(viewport(layout = grid.layout(nrow(layout), ncol(layout))))
		
		# Make each plot, in the correct location
		for (i in 1:numPlots) {
			# Get the i,j matrix positions of the regions that contain this subplot
			matchidx <- as.data.frame(which(layout == i, arr.ind = TRUE))
			
			print(plots[[i]], vp = viewport(layout.pos.row = matchidx$row,
											layout.pos.col = matchidx$col))
		}
	}
}