[R] Cumsum with a max and min value

[Gabor Grothendieck]

On Thu, Nov 25, 2010 at 3:44 PM, henrique <henrique at allianceasset.com.br> wrote:
> I have a vector of values -1, 0, 1, say
>
> a <- c(0, 1, 0, 1, 1, -1, -1, -1, 0, -1, -1)
>
> I want to create a vector of the cumulative sum of this, but I need to set a
> maximum and minimum value for the cumsum, for example:
>
> max_value <- 2
> min_value <- -2
> the expected result would be (0, 1, 1, 2, 2, 1, 0, -1, -1, -2, -2)
>

Try this:

f <- function(x, y) max(min(x + y, max_value), min_value)
Reduce(f, a, 0, accumulate = TRUE)[-1]

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