[R] filtering signals per day

[Henrique Dallazuanna]

Try this:

f$Filtered <- unlist(sapply(unstack(f, Signals ~ Dates),

function(.x)tabulate(which(as.logical(.x))[1], length(.x))))

On Wed, Mar 3, 2010 at 4:20 PM, anna <lippelanna24 at hotmail.com> wrote:
>
> Hello R lovers,
> I have a vector of dates and signals. I want to filter the signals per day
> in a way that only the first signal of the day remains like this:
> Dates               Signals       Filtered Signal
> 2006-11-02         0                    0
> 2006-11-02         1                    1
> 2006-11-02         0                    0
> 2006-11-02         1                    0
> 2006-11-02         1                    0
> 2006-11-02         0                    0
> 2006-11-03         1                    1
> 2006-11-03         1                    0
> 2006-11-03         0                    0
> 2006-11-03         1                    0
> 2006-11-03         0                    0
>
> The thing is that I want to do it with matrix functions and not doing a loop
> but I still have no clue even after having spent time on it. Can somebody
> please help me? thank you!
>
>
>
> -----
> Anna Lippel
> --
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> Sent from the R help mailing list archive at Nabble.com.
>
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-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O