[R] how to loop through names ?

[Pete Phillips]

Hi

I'm sure I'm missing something very straighforward here  :-(

I have a data set 'sales' as follows:
==========================================
# read in the sales data
sales<-read.table("sales.dat",header=TRUE);
#generate a serial field
sales$serial=c(1:24)

sales

   an  l ml  ne ni total serial
1  43 25 35  51 17 69    1
2  38 18 47  94 3  99    2
.......
24 58 13 41  95  4 1     24
===========================================

(extra rows and columns deleted).

I wish to produce a postscript plot file for each column plotted vs the
serial column, using either the 1st to 12th row or the 13th to 24th
rows, where the filename consists of the column name with '.ps' added.

This the code I have so far:

============================================
for (i in 1:(length(names(sales))-1)) {

fname <- paste(names(sales)[[i]],".ps",sep="")

postscript(file=fname)

plot(
sales$serial[13:24], 
sales[names(sales)[[i]]][13:24],
xlab="Month No", ylab="No/month")
 dev.off()

}
==============================================

The filename generation works (yay!), but I think I have missed
something very basic here as that plot line seems too complex (and
doesn't work!).

Any ideas please ?
 
Pete
--
Pete Phillips, Deputy Director,     |   http://www.smtl.co.uk/
Surgical Materials Testing Lab,     |   http://www.worldwidewounds.com/
Princess of Wales Hospital, S Wales |   http://www.dressings.org/
Tel/Fax: +44 1656-752820/30         |   pete at smtl.co.uk