Dear Kayj

Try something like

setwd("c:\\temp")
require(MASS)

my.df<-read.table("my_inputfile.txt", sep="\t", head=T)

my.df$newcol<-my.df$col1+my.df$col2+my.df$col3

write.table(my.df, "my_outputfile.txt", append=F, row.names=F, sep="\t")

On the above example, I suppose that your input file are on c:\temp
directory (pay attention on double slash); that you used TAB as field
separator (sep="\t"); that the first line of your input file have the
collumn names (head=T).

my.df$newcol will create a new collumn on your data.frame and that it will
receive the sum of other three collumns.

write.table will save your new table.

I hope this helps.

miltinho astronauta
Brazil



On 8/27/08, kayj <kjaja27@yahoo.com> wrote:
>
>
> I do have some data of dim 100*3 (i.e  100 rows and 3 columns ) stored in a
> txt file. I want to read the data into R,  Perform the same operation in
> each row and store the result in a forth column( that I should create).
> I do not know how I can create a forth column to store the result of the
> operation for each row?
>
>
>
>
>
> --
> View this message in context:
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> Sent from the R help mailing list archive at Nabble.com.
>
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