Hi Chris,

Is this what you have in mind?

> sum(with(yourdata, tapply(sus, id_r, function(x) any(x==0))))
[1] 13

HTH,
Jorge


On Wed, Apr 6, 2011 at 4:44 PM, Christopher Desjardins <> wrote:

> Hi,
> I have longitudinal school suspension data on students. I would like to
> figure out how many students (id_r) have no suspensions (sus), i.e. have a
> code of '0'. My data is in long format and the first 20 records look like
> the following:
>
> > suslm[1:20,c(1,7)]
>   id_r sus
>   11   0
>   15  10
>   16   0
>   18   0
>   19   0
>   19   0
>   20   0
>   21   0
>   21   0
>   22   0
>   24   0
>   24   0
>   25   3
>   26   0
>   26   0
>   30   0
>   30   0
>   31   0
>   32   0
>   33   0
>
> Each id_r is unique and I'd like to know the number of id_r that have a 0
> for sus not the total number of 0. Does that make sense?
> Thanks!
> Chris
>
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