[R] Selecting Variables

[Henrique Dallazuanna]

Try this:

data.frame(ID = x$ID,
                   Max_Exposure = max(rowSums(x[,-1] == "y")),
                   Unique_Exposure = rowSums(x[,-1] == "y"))

On Tue, Aug 5, 2008 at 10:21 AM, Michael Pearmain <mpearmain at google.com> wrote:
> Hi All,
>
> i have a dataset that i want to dynamically inspect for the number of
> variables that start with "Exposure_"  and then for these count the entries
> across each case i.e
>
> ID Exposure_1 Exposure_2 Exposure_3
> 1        y                 y                y
> 2        y                 y                -
> 3        y                 -                 -
>
> So the corresponding new variables that would be created are
>
> ID Max_Exposure Unique_Exposure
> 1           3                       3
> 2           3                       2
> 3           3                       1
>
> I know this may seem fairly basic but it will give me the starting point to
> develop more advanced things with loop and nat lang
>
> Thanks in advance
>
> Mike
>
>        [[alternative HTML version deleted]]
>
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-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O