How do you draw a boxplot without specifying x axis?

Question

The base graphics can nicely plot a boxplot using a simple command

data(mtcars)
boxplot(mtcars$mpg)

Answer 1

You have to provide some dummy value to x. theme() elements are used to remove x axis title and ticks.

ggplot(mtcars,aes(x=factor(0),mpg))+geom_boxplot()+
   theme(axis.title.x=element_blank(),
    axis.text.x=element_blank(),
    axis.ticks.x=element_blank())

Or using qplot() function:

qplot(factor(0),mpg,data=mtcars,geom='boxplot')

Answer 2

You can also use latticeExtra, to mix boxplot syntax and ggplot2-like theme:

bwplot(~mpg,data =mtcars,
        par.settings = ggplot2like(),axis=axis.grid)

Answer 3

you can set the x aesthetics to factor(0) and tweak the appearance by removing unwanted labels:

ggplot(mtcars, aes(x = factor(0), mpg)) +
    geom_boxplot() + 
    scale_x_discrete(breaks = NULL) +
    xlab(NULL)