How do I save or plot from within lists - r

I have named lists of entities (objects, lists, grobs?), from qplot or ggplot, that render or save just fine on their own, but I can't figure out how to pass them as a list or vector for arrangement. I believe my issue is with extracting list objects generally rather than with ggplot2.
library(ggplot2)
library(grid)
library(gridExtra)
# Generate a named list of ggplots
plotlist <- list()
for(a in c(1:4)) {
for(b in c(1:4)) {
plotlist[[paste0("Z",a,b)]] <-
qplot(rnorm(40,a,b),
geom="histogram",
xlab=paste0("Z",a,b))
}
}
# Arrange and display them
# The following two lines work fine, so the plots are in there:
plotlist[["Z12"]]
ggsave(plot=plotlist[["Z12"]], filename="deletable.png")
# The following two lines complain about not being 'grobs'
grid.arrange(plotlist, widths=c(1,1), ncol=2)
grid.arrange(unlist(plotlist), widths=c(1,1), ncol=2)
Can I somehow cast them as grobs without naming them explicitly, or find an alternative to unlist that lets the grob out?

Use lapply(plotlist, ggplot2::ggplotGrob) to generate a list of ggplot2 grobs. This list of grobs can then be passed to gridExtra::grid.arrange.
For example:
library(ggplot2)
library(gridExtra)
plotlist <- list()
for(a in c(1:4)) {
for(b in c(1:4)) {
plotlist[[paste0("Z",a,b)]] <-
qplot(rnorm(40,a,b),
geom="histogram",
xlab=paste0("Z",a,b))
}
}
grid.arrange(grobs = lapply(plotlist, ggplotGrob), widths = c(1, 1), ncol = 2)

Related

Plot Layout of Base R Plots Saved by recordPlot() Function

I can use the recordPlot() function to save Base R plots in data objects:
plot(1:5, 1:5)
my_plot1 <- recordPlot()
plot(1:10, 1:10)
my_plot2 <- recordPlot()
plot(1:20, 1:20)
my_plot3 <- recordPlot()
I would like to draw these three plots in a grid of plots. Usually, I could use the layout function for this. However, this does not work when I want to draw plots created by recordPlot.
This does not work:
layout(matrix(c(1, 0, 2, 3), ncol = 2))
plot.new()
my_plot1
my_plot2
my_plot3
How can I draw a grid of plots saved by the recordPlot() function?
I recently had to solve a similar problem, below are two solutions that may work for you.
(1) use par() to specify numbers of rows/ columns:
# create objects with base plots
plot(rnorm(50),rnorm(50))
my_plot1 <- recordPlot()
plot(rnorm(50),rnorm(50))
my_plot2 <- recordPlot()
plot(rnorm(50),rnorm(50))
my_plot3 <- recordPlot()
# clear plots in workspace
plot.new()
# plot side by side
par(mfrow= c(1,3)) # specify rows (1) and columns (3) for plotting
my_plot1
my_plot2
my_plot3
(2) Save objects to a list and then use plot_grid (cowplot library) - this is good if you need to export the figure:
library(cowplot)
# create empty list
p <- list()
# save objects to list
plot(rnorm(50),rnorm(50))
p[[1]] <- recordPlot()
plot(rnorm(50),rnorm(50))
p[[2]] <- recordPlot()
plot(rnorm(50),rnorm(50))
p[[3]] <- recordPlot()
# clear plots
plot.new()
# plot in 3 columns using plot_grid
plot_grid(plotlist = p, nrow=1, ncol=3)

How to save multiple ggplot charts in loop for using grid.arrange

I have a for loop that creates a different ggplot for a different set of parameters each time through the loop. Right now I am printing N different charts one at a time. I would like to save them so I can use grid.arrange to put them all on one page. This doesn't work:
p <- vector(length = N)
for(i in 1:N)
p[i] <- ggplot( ........
...
...
grid.arrange(p[1], p[2], .. p[N], nrow = 4)
Is there a way to save the plots for later plotting a grid of plots on a page outside the loop, or is there a way to set up the grid specification before the loop and and produce the gridded plot on the fly as the loop is executed (e.g., the way par is used with plot)?
You rarely want to use for loops in R. In R's lapply(). In a single step:
do.call(
grid.arrange,
lapply(data, function(f){
ggplot(f, ...)
}
)
EDIT:
If you want to store the list for later plotting:
plot_objects <- lapply(data, function(f) {
ggplot(f, ...)
})
do.call(grid.arrange, plot_objects)
This could be solved by initiating a list to store the plot objects instead of vector
p <- vector('list', N)
for(i in seq_len(N)) {
p[[i]] <- ggplot(...)
}
grid.arrange(p[[1]], p[[2]], ..., p[[N]], nrow = 4)

Retrieve facet labels from a ggplot or a gtable/gTree/grob/gDesc object

I have data I'm plotting using ggplot's facet_grid:
My data:
species <- c("spcies1","species2")
conditions <- c("cond1","cond2","cond3")
batches <- 1:6
df <- expand.grid(species=species,condition=conditions,batch=batches)
set.seed(1)
df$y <- rnorm(nrow(df))
df$replicate <- 1
df$col.fill <- paste(df$species,df$condition,df$batch,sep=".")
My plot:
integerBreaks <- function(n = 5, ...)
{
library(scales)
breaker <- pretty_breaks(n, ...)
function(x){
breaks <- breaker(x)
breaks[breaks == floor(breaks)]
}
}
library(ggplot2)
p <- ggplot(df,aes(x=replicate,y=y,color=col.fill))+
geom_point(size=3)+facet_grid(~col.fill,scales="free_x")+
scale_x_continuous(breaks=integerBreaks())+
theme_minimal()+theme(legend.position="none",axis.title=element_text(size=8))
which gives:
Obviously the labels are long and come out pretty messed up in the figure so I was wondering if there's a way edit these labels in the ggplot object (p) or the gtable/gTree/grob/gDesc object (ggplotGrob(p)).
I am aware that one way of getting better labels is to use the labeller function when the ggplot object is created but in my case I'm specifically looking for a way to edit the facet labels after the ggplot object has been created.
As I mentioned in the comments, the facet names are nested quite deeply within the gtable that ggplotGrob() gives you. However, this is still possible and since the OP explicitly wants to edit them after being plotted, you can do this with:
library(grid)
gg <- ggplotGrob(p)
edited_grobs <- mapply(FUN = function(x, y) {
x[["grobs"]][[1]][["children"]][[2]][["children"]][[1]][["label"]] <- y
return(x)
},
gg$grobs[which(grepl("strip-t",gg$layout$name))],
unique(gsub("cond","c", df$condition)),
SIMPLIFY = FALSE)
gg$grobs[which(grepl("strip-t",gg$layout$name))] <- edited_grobs
grid.draw(gg)
Note that this extracts all the strips using gg$grobs[which(grepl("strip-t",gg$layout$name))] and passes them to the mapply to be reset with the gsub(...) that OP specified in their comment.
In general, if you want to access just one of the text labels, there is a very similar structure which I made use of in my mapply:
num_to_access <- 1
gg$grobs[which(grepl("strip-t",gg$layout$name))][[num_to_access]][["grobs"]][[1]][["children"]][[2]][["children"]][[1]]$label
So to access the 4th label for example all you would need to do is change num_to_acces to be 4. Hope this helps!

plotting a list of grobs

DISCLOSURE: I'm not sure how to make a reproducible example for this question.
I'm trying to plot a list of grobs using the gridExtra package.
I have some code that looks like this:
## Make Graphic Objects for Spec and raw traces
for (i in 1:length(morletPlots)){
gridplots_Spec[[i]]=ggplotGrob(morletPlots[[i]])
gridplots_Raw[[i]]=ggplotGrob(rawPlot[[i]])
gridplots_Raw[[i]]$widths=gridplots_Spec[[i]]$widths
}
names(gridplots_Spec)=names(morletPlots)
names(gridplots_Raw)=names(rawPlot)
## Combine spec and Raw traces
g=list()
for (i in 1:length(rawPlot)){
g[[i]]=arrangeGrob(gridplots_Spec[i],gridplots_Raw[i],heights=c(4/5,1/5))
}
numPlots = as.numeric(length(g))
##Plot both
for (i in 1:numPlots){
grid.draw(g[i],ncol=2)
}
Let me walk through the code.
morletPlots = a list of ggplots
rawplot = A list of ggplots
gridplots_spec and gridplots_Raw = list of grobs from the ggplots made above.
g = a list of the two grobs above combined so combining gridplots_spec[1] and gridplots_raw[1] so on and so on for the length of the list.
now my goal would be two plot all of those into 2 columns. But whenever I pass the gridplots_spec[i] through the grid.draw loop I get an error:
Error in UseMethod("grid.draw") :
no applicable method for 'grid.draw' applied to an object of class "list"
I can't unlist it becasue it just turns into a long character vector. any ideas?
If it's absolutely crucial I can spend the time to make an reproducible example but I'm more likely just missing a simple step.
Here's my interpretation of your script, if it's not the intended result you may want to use some bits and pieces to make your question reproducible.
library(grid)
library(gridExtra)
library(ggplot2)
morletPlots <- replicate(5, ggplot(), simplify = FALSE)
rawplot <- replicate(5, ggplot(), simplify = FALSE)
glets <- lapply(morletPlots, ggplotGrob)
graws <- lapply(rawplot, ggplotGrob)
rawlet <- function(raw, let, heights=c(4,1)){
g <- rbind(let, raw)
panels <- g$layout[grepl("panel", g$layout$name), ]
# g$heights <- grid:::unit.list(g$heights) # not needed
g$heights[unique(panels$t)] <- lapply(heights, unit, "null")
g
}
combined <- mapply(rawlet, raw = graws, let=glets, SIMPLIFY = FALSE)
grid.newpage()
grid.arrange(grobs=combined, ncol=2)
Edit I can't resist this mischievous hack to colour the plots for illustration; feel free to ignore it.
palette(RColorBrewer::brewer.pal(8, "Pastel1"))
ggplot.numeric = function(i) ggplot2::ggplot() +
theme(panel.background=element_rect(fill=i))
morletPlots <- lapply(1:5, ggplot)
rawplot <- lapply(1:5, ggplot)

How can I arrange an arbitrary number of ggplots using grid.arrange?

This is cross-posted on the ggplot2 google group
My situation is that I'm working on a function that outputs an arbitrary number of plots (depending upon the input data supplied by the user). The function returns a list of n plots, and I'd like to lay those plots out in 2 x 2 formation. I'm struggling with the simultaneous problems of:
How can I allow the flexibility to be handed an arbitrary (n) number of plots?
How can I also specify I want them laid out 2 x 2
My current strategy uses grid.arrange from the gridExtra package. It's probably not optimal, especially since, and this is key, it totally doesn't work. Here's my commented sample code, experimenting with three plots:
library(ggplot2)
library(gridExtra)
x <- qplot(mpg, disp, data = mtcars)
y <- qplot(hp, wt, data = mtcars)
z <- qplot(qsec, wt, data = mtcars)
# A normal, plain-jane call to grid.arrange is fine for displaying all my plots
grid.arrange(x, y, z)
# But, for my purposes, I need a 2 x 2 layout. So the command below works acceptably.
grid.arrange(x, y, z, nrow = 2, ncol = 2)
# The problem is that the function I'm developing outputs a LIST of an arbitrary
# number plots, and I'd like to be able to plot every plot in the list on a 2 x 2
# laid-out page. I can at least plot a list of plots by constructing a do.call()
# expression, below. (Note: it totally even surprises me that this do.call expression
# DOES work. I'm astounded.)
plot.list <- list(x, y, z)
do.call(grid.arrange, plot.list)
# But now I need 2 x 2 pages. No problem, right? Since do.call() is taking a list of
# arguments, I'll just add my grid.layout arguments to the list. Since grid.arrange is
# supposed to pass layout arguments along to grid.layout anyway, this should work.
args.list <- c(plot.list, "nrow = 2", "ncol = 2")
# Except that the line below is going to fail, producing an "input must be grobs!"
# error
do.call(grid.arrange, args.list)
As I am wont to do, I humbly huddle in the corner, eagerly awaiting the sagacious feedback of a community far wiser than I. Especially if I'm making this harder than it needs to be.
You're ALMOST there! The problem is that do.call expects your args to be in a named list object. You've put them in the list, but as character strings, not named list items.
I think this should work:
args.list <- c(plot.list, 2,2)
names(args.list) <- c("x", "y", "z", "nrow", "ncol")
as Ben and Joshua pointed out in the comments, I could have assigned names when I created the list:
args.list <- c(plot.list,list(nrow=2,ncol=2))
or
args.list <- list(x=x, y=y, z=x, nrow=2, ncol=2)
Try this,
require(ggplot2)
require(gridExtra)
plots <- lapply(1:11, function(.x) qplot(1:10,rnorm(10), main=paste("plot",.x)))
params <- list(nrow=2, ncol=2)
n <- with(params, nrow*ncol)
## add one page if division is not complete
pages <- length(plots) %/% n + as.logical(length(plots) %% n)
groups <- split(seq_along(plots),
gl(pages, n, length(plots)))
pl <-
lapply(names(groups), function(g)
{
do.call(arrangeGrob, c(plots[groups[[g]]], params,
list(main=paste("page", g, "of", pages))))
})
class(pl) <- c("arrangelist", "ggplot", class(pl))
print.arrangelist = function(x, ...) lapply(x, function(.x) {
if(dev.interactive()) dev.new() else grid.newpage()
grid.draw(.x)
}, ...)
## interactive use; open new devices
pl
## non-interactive use, multipage pdf
ggsave("multipage.pdf", pl)
I'm answering a bit late, but stumbled on a solution at the R Graphics Cookbook that does something very similar using a custom function called multiplot. Perhaps it will help others who find this question. I'm also adding the answer as the solution may be newer than the other answers to this question.
Multiple graphs on one page (ggplot2)
Here's the current function, though please use the above link, as the author noted that it's been updated for ggplot2 0.9.3, which indicates it may change again.
# 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) {
require(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))
}
}
}
One creates plot objects:
p1 <- ggplot(...)
p2 <- ggplot(...)
# etc.
And then passes them to multiplot:
multiplot(p1, p2, ..., cols = n)

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