boxplot via plot command

Hi,
Antje <niederlein-rstat <at> yahoo.de> writes:

Hi folks,

I've just discovered that the following code leads to boxplot 
(surprisingly to me).
Can anybody explain to me why? Is this documented somewhere? I've never 
consider this option before.

x <- rnorm(300)
l <- c(rep("label1",100), rep("label2",50), rep("label3",150))

df <- data.frame(as.factor(l), x)
plot(df)

Thank you!
Antje

You can follow this through the various methods.  If you look
at plot.data.frame  

getAnywhere(plot.data.frame)  

You'll see that when the data.frame has only 2 columns, it
calls plot with the first two arguments.  Since the first argument
here is a factor, it dispatches to the plot.factor method

getAnywhere(plot.factor)

from which you'll see that under your circumstances it will call 
boxplot

HTH,

Ken