[R] local sequence function

[Dimitris Rizopoulos]

try the following:

v <- c(NA,NA,TRUE,TRUE,NA,TRUE,NA,TRUE,TRUE,TRUE)

l <- as.numeric(!is.na(v))
tmp <- cumsum(l)
tmp - cummax((!l) * tmp)


I hope it helps.

Best,
Dimitris


smu wrote:
> hey,
> 
> I can not find a function for the following problem, hopefully you can
> help me.
> 
> I have a vactor like this one
> 
> v = c(NA,NA,TRUE,TRUE,NA,TRUE,NA,TRUE,TRUE,TRUE)
> 
> and I would like to the TRUE values by the their "local sequence
> number".
> 
> This means, the result should look thike this:
> 
> c(NA,NA,1,2,NA,1,NA,1,2,3)
> 
> Of course I could solve the problems using a loop, but this would be
> much to slow, because the real vector is much larger.
> Can you point me in the right direction?
> 
> thank you!
> 
> regards,
>  Stefan
> 
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-- 
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center

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