All you need to try out in this recipe is to run R and type the recipe in the command prompt. You can also choose to save the recipe as a script so that you can use it again later on.

Let's say we want to create an L-shaped box around a graph such that the default top and right borders are not drawn. We can do so using the bty argument in the par() command:

par(bty="l")
plot(rnorm(100))

The bty argument stands for the box type and takes single characters in inverted commas as values. The resulting box resembles the corresponding uppercase letter. For example, the default value is o, thus creating a box with all four edges. Other possible values are l, 7, c, u, and ]. If we do not wish to draw a box at all, we can set bty to n.

Box styles can be controlled in a finer way using the box() command. In addition to the lty and lwd arguments, we can also specify where the box should be drawn using the which parameter, which can take values of plot, figure, inner, and outer.

Let's say we want to draw a graph with an L-shaped box for the plot area and a full box around the figure including the axis annotations and titles. Then, we can use the following code:

par(oma=c(1,1,1,1))
plot(rnorm(100),bty="l")
box(which="figure")

Note that we had to first set the outer margins by setting the oma argument with the par() function. You will learn more about this argument later in this chapter. If we did not set the outer margins, the box around the figure would be right at the edge of the plot and get cut off because the default margins are set to zero.