[R] need help in customising function in stat_summary function ggplot2

William Dunlap wdunlap at tibco.com
Thu Oct 20 18:17:29 CEST 2016

Your code,
  cnt = 0
  for(i in 1:length(x)){
   ifelse(x[i] > median(x),cnt+1,cnt)
sets cnt to zero and never sets it to anything else.  Hence it is zero
at the end of the loop.  if you set cnt to the value of your call to ifelse
you should get the desired result
    cnt <- ifelse(x[i] > median(x),cnt+1,cnt)

By the way, the more R-ish way of counting the number of x strictly
greater than the median is just
   cnt <- sum(x > median(x))
instead of those 4 lines above.
('cnt' should be about length(x)/2 unless there are a lot of points at the

Bill Dunlap
TIBCO Software
wdunlap tibco.com

On Thu, Oct 20, 2016 at 1:25 AM, Indhira, Anusha <
Anusha.Indhira at controlsdata.com> wrote:

> Hi,
> I would like to print percentage of points in a group which are greater
> than median value in boxplot. I have tried below code but it always prints
> zero in the graph. Can you let me know, how to modify code to get desired
> result?
> perc.greaterthan.median <- function(x){
>   cnt = 0
>   for(i in 1:length(x)){
>    ifelse(x[i] > median(x),cnt+1,cnt)
>   }
>   return(c(y = median(x)*1.7, label = round((cnt/length(x))*100,2)))
> }
> ggplot(st_chg_51, aes(x=factor(st_dv), P3))+ #label=rownames(st_chg_51))) +
>   geom_boxplot(fill = "grey80", colour = "#3366FF") +
>   stat_summary(fun.data = perc.greaterthan.median, geom = "text", fun.y =
> median) +
>   theme_bw()+theme(axis.text = element_text(angle = 90, hjust = 1))
> Why does cnt in the function doesn't get incremented in the loop?
> Thanks,
> Anusha
> This e-mail (including attachments) contains contents owned by Rolls-Royce
> plc and its subsidiaries, affiliated companies or customers and covered by
> the laws of England and Wales, Brazil, US, or Canada (federal, state or
> provincial). The information is intended to be confidential and may be
> legally privileged. If you are not the intended recipient, you are hereby
> notified that any retention, dissemination, distribution, interception or
> copying of this communication is strictly prohibited and may subject you to
> further legal action. Reply to the sender if you received this email by
> accident, and then delete the email and any attachments.
>         [[alternative HTML version deleted]]
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/
> posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

	[[alternative HTML version deleted]]

More information about the R-help mailing list