This post explains how to build grouped, stacked and percent stacked barplot with base R. It provides a reproducible example with code for each type.
A grouped barplot display a numeric value for a set of entities
split in groups and subgroups. Before trying to build one, check how
to make a basic barplot with
R
and ggplot2
.
A few explanation about the code below:
barplot()
function will recognize this format,
and automatically perform the grouping for you.
beside
allows to toggle between the grouped and
the stacked barchart
# Create data
set.seed(112)
data <- matrix(sample(1:30,15) , nrow=3)
colnames(data) <- c("A","B","C","D","E")
rownames(data) <- c("var1","var2","var3")
# Grouped barplot
barplot(data,
col=colors()[c(23,89,12)] ,
border="white",
font.axis=2,
beside=T,
legend=rownames(data),
xlab="group",
font.lab=2)
A stacked barplot is very similar to the grouped barplot above. The
subgroups are just displayed on top of each other, not beside. The
stacked barchart is the default option of the
barplot()
function in base R, so you donâ€™t need to use
the beside
argument.
# Create data
set.seed(112)
data <- matrix(sample(1:30,15) , nrow=3)
colnames(data) <- c("A","B","C","D","E")
rownames(data) <- c("var1","var2","var3")
# Get the stacked barplot
barplot(data,
col=colors()[c(23,89,12)] ,
border="white",
space=0.04,
font.axis=2,
xlab="group")
A percent stacked barchart displays the evolution of the proportion of each subgroup. The sum is always equal to 100%.
In base R, you have to manually compute the percentages, using the
apply()
function. This is more straightforward using
ggplot2.
Note that here, a custom color palette is used, thanks to the
RColorBrewer
package.
# Create data
set.seed(1124)
data <- matrix(sample(1:30,15) , nrow=3)
colnames(data) <- c("A","B","C","D","E")
rownames(data) <- c("var1","var2","var3")
# create color palette:
library(RColorBrewer)
coul <- brewer.pal(3, "Pastel2")
# Transform this data in %
data_percentage <- apply(data, 2, function(x){x*100/sum(x,na.rm=T)})
# Make a stacked barplot--> it will be in %!
barplot(data_percentage, col=coul , border="white", xlab="group")