[R] multiple boxplots using boxplot

[Marek Bartkuhn]

Hi,

I have data in 3 vectors a,b and c looking like

eg  a: 		1.2		3.4		1.4 ......


I like to have the data from each vector as a boxplot, but the 3  
boxplots within one graph.

One example is the first graph  at

http://www.statmethods.net/graphs/boxplot.html

Unfortunately I do not really understand the corresponding  
description. The vectors are of different length, therefore R  
complains when I try to build a data.frame of the 3 vectors:

arguments imply differing number of rows: 6175, 20, 190

What do I have to do?

Marek