R help - Jun 2005 - how to generate pairwise plots with data frames - tia

hi -

sorry for a newbie question, but I've tried to go through the 
documentation and couldn't find anything that would address my specific 
need.

in a nutshell, I have a txt file containing a data matrix with 10 
columns of data.  I would like to generate pairwise plots of the data, 
i.e. 1 column against the other 9.  Since this will produce 50 plots, 
I'd like to do it using a loop.  However, I can't figure out how to do 
it as it seems like I have to specify the column name within the plot 
function.

for example, if I have:

    test <- read.delim("matrix.txt")

and then try to generate a plot of the first 2 columns via:

    plot(test[1], test[2)

I get an error message:

    Error in pmatch(x, table, duplicates.ok) :
            argument is not of mode character

but if I specify these columns by their column headers, i.e.:

    attach(test)
    plot(Control_200, Control_201)

it works just fine.  However, with 10 columns, this will produce ~ 50 
pairwise plots, so I'd really like to figure out how to automate this.  
I've tried getting the names of the data frame and using those, i.e.:

    myNames<-names(test)
    plot(test$myNames[1], test$myNames[2])

but that doesn't work either as the myNames members are strings, not the 
variables themselves (I believe).

is it possible to get a listing of the variables themselve, not the 
names and work off of those?

thanks to anyone who can help shed some light on this,

Peter Waltman

Peter,

Please read the intro to R available on the R web page - you've run
into a subsetting problem. The code you specified doesn't select a
column from your matrix.
>     plot(test[1], test[2)
Try:

plot(test[,1], test[,2])

since test is a two-dimensional construct.

Also see

?pairs


-- 
Sarah Goslee
http://www.stringpage.com