This should do it for you:

> x <- c( TRUE, TRUE, TRUE, FALSE, FALSE, TRUE, TRUE, FALSE, TRUE );
> y <- rle(x)
> unlist(lapply(seq(length(y$lengths)), function(.indx){
+     if (y$values[.indx]) seq(y$lengths[.indx])
+     else rep(0, y$lengths[.indx])
+ }))
[1] 1 2 3 0 0 1 2 0 1



On 6/19/07, Feng, Ken <ken.feng@citi.com> wrote:
>
> Hi,
>
> I start with an array of booleans:
>
>        x <- c( TRUE, TRUE, TRUE, FALSE, FALSE, TRUE, TRUE, FALSE, TRUE );
>
> I want to define an y <- f(x) such that:
>
>        y <- c( 1, 2, 3, 0, 0, 1, 2, 0, 1 );
>
> In other words, do a cumsum when I see a TRUE, but reset to 0 if I see a
> FALSE.
>
> I know I can do this with a very slow and ugly loop or maybe use apply,
> but I was hoping there are some R experts out there who can show me
> a cleaner/more elegant solution?
>
> Thanks in advance.
>
> - Ken
>
> ______________________________________________
> R-help@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

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