R help - Mar 2012 - How to get the most frequent value of the subgroup

Dear Members of the R-Help,


While using a R function - 'aggregate' that you developed, I become to
have a question.

In that function,


> aggregate(x, by, FUN, ..., simplify = TRUE)


I was wondering about what type of FUN I should write if I want to get "the
most frequent value of the subgroup" as a summary statistics of the
subgroups.

I will appreciate if I can get your idea on this issue.

Many thanks,

Jason Jung.


	[[alternative HTML version deleted]]

Dear Members of the R-Help,



While using a R function - 'aggregate' that you developed, I become to
have
a question.

In that function,


> aggregate(x, by, FUN, ..., simplify = TRUE)


I was wondering about what type of FUN I should write if I want to get "the
most frequent value of the subgroup" as a summary statistics of the
subgroups.

I will appreciate if I can get your idea on this issue.



Many thanks,



Jason Jung.

	[[alternative HTML version deleted]]

What you are looking for is commonly called the mode, but
(surprisingly?) there doesn't seem to be a standard implementation for
mode() in R. (the mode function gives you something else entirely) --
this SO thread may be of help:
http://stackoverflow.com/questions/2547402/standard-library-function-in-r-for-finding-the-mode

Michael

On Thu, Mar 29, 2012 at 9:30 AM, Jung, Yongsuhk <yjung.phd at ivey.ca>
wrote:
> Dear Members of the R-Help,
>
>
> While using a R function - 'aggregate' that you developed, I become
to have a question.
>
> In that function,
>
>
>
>> aggregate(x, by, FUN, ..., simplify = TRUE)
>
>
>
> I was wondering about what type of FUN I should write if I want to get
"the most frequent value of the subgroup" as a summary statistics of
the subgroups.
>
> I will appreciate if I can get your idea on this issue.
>
> Many thanks,
>
> Jason Jung.
>
>
> ? ? ? ?[[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> 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.

On Mar 29, 2012, at 9:30 AM, Jung, Yongsuhk wrote:
> Dear Members of the R-Help,
>
>
> While using a R function - 'aggregate' that you developed, I become
> to have a question.
>
> In that function,
>
>> aggregate(x, by, FUN, ..., simplify = TRUE)
>
> I was wondering about what type of FUN I should write if I want to  
> get "the most frequent value of the subgroup" as a summary  
> statistics of the subgroups.
Something along the lines of

  function(x){  tbl <- table(x);  retrun(names(tbl)[which.max(tbl)] }

You could also search for definitions that have appeared over the  
years in rhelp for a mode function (but not the existing mode function  
which is not designed to deliver what you request.)
>
> 	[[alternative HTML version deleted]]
-- 

David Winsemius, MD
West Hartford, CT