[R] the first. from SAS in R

[Gustavo Carvalho]

Perhaps something like this:

a$d <- ifelse(duplicated(a$a), 0, 1)

On Tue, Nov 23, 2010 at 1:33 PM, Joel <joda2457 at student.uu.se> wrote:
>
> Is there any similar function in R to the first. in SAS?
>
> What it dose is:
>
> Lets say we have this table:
>
>  a b  c
>  1 1  5
>  1 0  2
>  2 0  2
>  2 0 NA
>  2 9  2
>  3 1  3
>
>
> and then I want do to do one thing the first time the number 1 appers in a
> and something else the secund time 1 appers in a and so on.
>
> so
>
> something similar to:
>
> if first.a {
>  a$d<-1
> }else{
>  a$d<-0
> }
>
> This would give me
>
>  a b  c b
>  1 1  5 1
>  1 0  2 0
>  2 0  2 1
>  2 0 NA 0
>  2 9  2 0
>  3 1  3 1
>
> Is there such a function in R or anything similar?
>
>
> thx
>
> //Joel
>
> --
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