Try this:



func <- function(x)
{
which.negative <- which(x<0)
index.to.return <- which.negative[which.negative > which.max(x)][1]
return(index.to.return)
}

func(x)


Best,
Tal

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On Mon, Apr 26, 2010 at 7:29 PM, Su Chu <sushikyc@gmail.com> wrote:

> Hi there,
>
> I am working on a project that requires me to find the point at which
> values
> become negative in a sequence about the max.
>
> For example, say I have some sequence:
>
> x=c(-12, -2,-19, 0, -14, -2, 9,10,20,35,56,89,60,39,12,8,-5,-2,0,10)
>
> In this sequence, the max is 89, and I need to identify that -2 and -5 are
> the points at which the values* first *become negative about the max and
> retrieve their index values.
>
> I was hoping for some help in finding a way to automate this procedure, as
> I
> have over 100 vectors of this kind where I must find the two values about
> the max.
>
> Could anyone help? I would really, really appreciate it!
>
>
> Thank you so much!
>
> Best,
> Su
>
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>
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>

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