R help - Jan 2011 - how to keep keep matching column in output of merge

How do I keep the linking column[s] in a merge()?
  I need to use the values again in a further merge.

thanks

Nevil Amos

Nevil Amos <nevil.amos <at> gmail.com> writes:
> How do I keep the linking column[s] in a merge()?
>   I need to use the values again in a further merge.
  simple reproducible example please?
(e.g. make up a couple of 4-row datasets that show what you
want, what you are trying, and what you are getting instead).

Hi Nevil,

We really need an example here of what you're doing, since
merge() does keep the id column by default.

> x <- data.frame(id = c("a", "b", "c",
"d"), x=c(1,2,3,4))
> y <- data.frame(id = c("b", "a", "d",
"c"), y=c(101, 102, 103, 104))
> merge(x, y)
  id x   y
1  a 1 102
2  b 2 101
3  c 3 104
4  d 4 103

Sarah

On Tue, Jan 4, 2011 at 8:31 AM, Nevil Amos <nevil.amos at gmail.com>
wrote:
> How do I keep the linking column[s] in a merge()?
> ?I need to use the values again in a further merge.
>
> thanks
>
> Nevil Amos
>
-- 
Sarah Goslee
http://www.functionaldiversity.org