Hi Miao, If I understand your question correctly, you want to get a return value from the "multiplot" function that you have copied into your message. You could simply add:
return(plotlist) just before the final right brace in the function and it would return the list of plots that you have created. However, as you already have this, I think you probably want to get a single plot object that has all the information in the original plotlist. This doesn't seem possible to me as I don't think that the ggplot objects can be merged. I may be mistaken, so I will defer to anyone more knowledgeable. Jim On Fri, Jan 15, 2016 at 4:26 PM, jpm miao <miao...@gmail.com> wrote: > Hi, > > The function "ggplot" does plot and return a plot. For example, we can > write: > > y = ggplot(.. .....) Then y is a plot. > > How can we modify the multiplot function so that it can also return a > plot? Multiplot.R is here: > > http://www.cookbook-r.com/Graphs/Multiple_graphs_on_one_page_(ggplot2)/ > , > and the code is as below. > > Any advice on returning a multi-ggplot would help! > > Thanks, > > Miao > > # Multiple plot function # # ggplot objects can be passed in ..., or to > plotlist (as a list of ggplot objects) # - cols: Number of columns in > layout # > - layout: A matrix specifying the layout. If present, 'cols' is ignored. # > # > If the layout is something like matrix(c(1,2,3,3), nrow=2, byrow=TRUE), # > then plot 1 will go in the upper left, 2 will go in the upper right, and # > 3 will go all the way across the bottom. # 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)) } } } > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.