# [R] calculate row median of every three columns for a dataframe

Bert Gunter bgunter@4567 @end|ng |rom gm@||@com
Thu Apr 16 16:47:10 CEST 2020

```You have *not* calculated row medians for all combinations of (is that
what you meant?) 3 columns of your data frame.
?combn  with column indexing can help you do that. If that is not what
you meant, then ??

Bert Gunter

"The trouble with having an open mind is that people keep coming along
and sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )

On Thu, Apr 16, 2020 at 7:32 AM aiguo li via R-help
<r-help using r-project.org> wrote:
>
>  Hi all,
> I need to calculate a row median for every three columns of a dataframe.  I made it work using the following script, but not happy with the script.  Is there a simpler way for doing this?
> df = data.frame("a"=c(2,3,4), "b"=c(3,5,1),"c"=c(1,3,6),"d"=c(7,2,1),"e"=c(2,5,3),"f"=c(4,5,1))tmed <- function(dt) {x = apply(dt,1,median); return(x)}n =seq(1, ncol(df),3)w=0;for (i in n) {   m=i+2;  dt = df[,i:m];   y=tmed(dt);    w = cbind(w,y)}t.med <- w[,2:3]
> Thanks,
> Anna
>
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help