[R] Boxplot Help for Neophyte

[Marc Schwartz (via MN)]

On Mon, 2006-02-20 at 20:27 +0000, Alex Park wrote:
> R helpers
> 
> I am getting to grips with R but came across a small problem today that I 
> could not fix by myself.
> 
> I have 3 text files, each with a single column of data. I read them in 
> using:
> 
> myData1<-scan("C:/Program Files/R/myData1.txt")
> myData2<-scan("C:/Program Files/R/myData2.txt")
> myData3<-scan("C:/Program Files/R/myData3.txt")
> 
> I wanted to produce a chart with 3 boxplots of the data and used:
> 
> boxplot(myData1, myData2, myData3)
> 
> This worked fine so I consulted R [help(bxp)] to add some format and labels 
> e.g. title= , xlab =, ylab= , notch=TRUE etc. I managed to figure that ok.
> 
> However, I could not figure out how to get the labels myData1, myData2, and 
> myData3 on the boxplot x-axis to denote which box was which (though I knew 
> by looking). Can anybody help with this?
> 
> I trawled through my downloaded R pdfs but could not find a way.
> 
> Regards
> 
> 
> Alex Park


Alex,

You can use the 'names' argument to boxplot():

  boxplot(myData1, myData2, myData3, 
          names = c("myData1", "myData2", "myData"))

If you want additional flexibility, note that by default (unless you
change the 'at' argument), the group plots are drawn at integer axis
values of 1:n, where 'n' is the number of groups. See the 'at' argument
in ?boxplot.  You can then use mtext() to draw further text if desired.

HTH,

Marc Schwartz