[R] Discover significant change in sorted vector

Jim Lemon jim at bitwrit.com.au
Wed Apr 22 14:02:13 CEST 2009


Hans-Henning Gabriel wrote:
> Hi,
>
> suppose I have a simple sorted vector like this:
>
> a <- c(2,3,3,5,6,8,8,9,15, 25, 34,36,36,38,41,43,44,44,46);
>
> Is there a function in R, I can use to discover that from index 8 to 
> index 11 the values are changing significantly?
> The function should return a value pointing to one of the indices 8, 
> 9, 10 or 11. Any of them would be fine.
> The difficulty is that there may be no big gap. I mean, indices 8 and 
> 11 are somehow "connected" by indices 9 and 10. So, it's not an option 
> to just search for biggest difference between the values.
>
> Perfect would be a function that is able to discover multiple changes 
> if it is present in the data.
>
Hi Henning,
Is max(diff(a)) any good to you?

Jim




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