[R-sig-teaching] length of vectors with tapply
Mark Daniel Ward
mdw at purdue.edu
Wed Sep 10 05:16:23 CEST 2014
Dear Steven,
If you remove the parameter:
na.rm=TRUE
then your example seems to work fine for me. Good luck!
Best wishes,
Mark
Mark Daniel Ward, Ph.D.
Associate Professor and Undergraduate Chair
Department of Statistics
Purdue University
150 North University Street
West Lafayette, IN 47907-2067
mdw at purdue.edu
phone: (765) 496-9563
On 9/9/14, 11:12 PM, Steven Stoline wrote:
> Dear All:
>
> I was trying to get the lengths of vectors using "length" in tapply as
> follows:
>
> ni<-tapply(data[,2], data[,2], length, na.rm=TRUE)
>
> but it did not work for me. I am not sure what I am doing wrong.
>
> I am not sure if I should use different function.
>
> Here is the data:
> ============
> data<-matrix(c(8,24,0,0,16,32,6,0,16,7,4,4,9,5,8,18,2,0,4,0,8,3,1,5,24,12,2,8,1,8,
> 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,3,3),30,2)
>
>
>
> The answer should be:
>
> ni: 18 , 10 , 2
>
>
> thank you very much
> Steven
>
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