Creating stratified histogram using an R function - r

Question

I am trying to create this stratified histogram on R, however I am not getting the right plot. I would like to use the rect function as well if possible.
How would I write an R function to create this stratified histogram using the iris dataset in R?
This is the code so far:
strathist = function(x, y, ylab = "Frequency", xlab = "", main = ""){
cols = hcl(h=seq(0, 360, by = 120))
h = hist(x, breaks = 24, plot = FALSE)
tb = table(y, cut(x, h$breaks))
plot.new()
barplot(tb, ylim = c(0, max(h$count)), col = cols,
ylab = ylab, xlab = xlab, main = main, axisnames = FALSE)
box()
axis(1, 0:(length(h$breaks)-1), h$breaks)
axis(2)
legend("topright", c(rownames(tb)), fill = cols)
}
with(iris, strathist(Sepal.Width, Species, xlab = "Sepal.Width", main = "Stratified Histogram"))

Answer 1

There are a few different ways to do this, if you insist on using R base, you could use two barplots, one to add the colors and one to add the boxes:
strathist = function(x,
y,
ylab = "Frequency",
xlab = "",
main = "") {
cols = hcl(h = seq(0, 360, by = 120))
h = hist(x,
breaks = 24,
plot = F)
tb = table(y, cut(x, h$breaks))
ylim <- c(-.05 * max(colSums(tb)),
1.25 * max(colSums(tb)))
barplot(
tb,
col = cols,
ylim = ylim,
ylab = ylab,
xlab = xlab,
main = main,
axisnames = FALSE,
border = NA,
space = 0
)
barplot(
colSums(tb),
ylim = ylim,
col = NA,
ylab = ylab,
xlab = xlab,
main = main,
axisnames = FALSE,
add = T,
space = 0
)
box()
axis(1, seq(0,
length(h$breaks) - 1,
by = 5),
seq(min(x),max(x), by = .5))
axis(2)
legend("topright", c(rownames(tb)), fill = cols,border = NA,)
}
with(
iris,
strathist(Sepal.Width, Species, xlab = "Sepal.Width", main = "Stratified Histogram")
)
Or you could go the somewhat easier route to use ggplot2:
library(ggplot2)
ggplot(iris,aes(x = Sepal.Width)) +
geom_histogram(bins = 25,aes(fill = Species)) +
geom_histogram(bins = 25, fill = NA, color = 'black') +
theme_minimal()
Created on 2020-09-13 by the reprex package (v0.3.0)