R help - Sep 1999 - count of factors

Hello,


I was used to count how many times every factor is found the following
way :

(assuming 'vect' is a vector of factors)
tapply(vect,vect,length)

but recently I experienced weird results with this

In fact, my command line was
tapply(ORGMORE[[1]][vect],ORGMORE[[1]][vect],length)
where
- 'vect' is a vector of indices
- 'ORGMORE[[1]]' is a slightly long vector of factors

In managed to get correct results using
tapply(paste(ORGMORE[[1]][vect]),paste(ORGMORE[[1]][vect]),length)

I am not sure the reason is the presence of NA values in ORGMORE[[1]],
or
the size of it because I tried unsuccessfully to reproduce this with an
another session
of R and a short vector having NA values.
....and 'vect' is the result of a previous tapply call.



In my opinion, I do not get what I want the good-safe way...


Any hints ?







Laurent

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On Thu, 2 Sep 1999, Laurent Gautier wrote:
> Hello,
> 
> 
> I was used to count how many times every factor is found the following
> way :
> 
> (assuming 'vect' is a vector of factors)
> tapply(vect,vect,length)
You could use table(vect) to count the number of times each level appears
in vect.


Thomas Lumley
Assistant Professor, Biostatistics
University of Washington, Seattle

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