Add more to a histogram in R
Add more to a histogram in R
A histogram is a standard way to present the distribution of a sample of numbers. A basic histogram is useful but it is easy to add more to a histogram in R to produce an even more informative plot. In this article you’ll see how to add a rug and a strip-chart to a basic historgram using simple R commands.
A basic histogram
It is easy to make a histogram using R with the hist() command. For example:
set.seed(123)
x <- norm(n = 50, mean = 10, sd = 1)
hist(x, col = "skyblue")
Produces a histogram resembling this:
Add a rug
A rug plot can be added to more or less any graphic. The rug() command can add the rug to any side of the plot:
side = 1is the bottom axisside = 2is the left axis
You can alter the colour and width of the rug lines using regular graphical parameters:
rug(x, side = 1, col = "blue")
Adds the rug like so:
Add a strip chart
A strip chart can also be added to any chart via the stripchart() command. However, you also need to specify add = TRUE to the command. Giving a bit of jitter helps to separate out points that are coincident:
stripchart(x,
method = "jitter",
pch = 23,
bg = "pink",
add = TRUE)
The final plot looks like so:
There are many additional options for the stripchart() command; use help(stripchart) in R to find out more. Look out for other articles in our Tips & Tricks pages.
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