[R] moving distance between two sets of data

[David Winsemius]

On Aug 19, 2012, at 12:04 PM, White, William Patrick wrote:

> On the surface this seems pretty simple, but I flummoxed. I have two  
> sets of numbers they bounce around zero, positive one and negative  
> one. They have a relationship between them, where one diverges away  
> from the other. I want create a second set of numbers that tracks  
> that divergence.
>
> #Lets make some data like mine, kinda
> Firstset <- runif(100, min = -1 , max =1)
> Secondset <- runif(100, min = -1 , max =1)
>
> #So something like:
> Divergence <- abs (Firstset - Secondset)
>
> #but this doesn't work because when Firstset is at .5 and Secondset  
> is at  -.25 it returns .25 instead of .75

   abs( .5 - (-.25) ) should NOT return .25 so you need to produce a  
better example or point to specifics in the example you offered. If  
what you wanting what you are getting, then use set.seed(123) and  
refer to specific values.

 > abs( .5 - (-.25) )
[1] 0.75

-- 
David.

>
> #another possibility is:
>
> Divergence <- abs (Firstset) - abs (Secondset)
>
> #but when Firstset is at .5 and Secondset is at -.5 it returns 0  
> instead of 1
>
> #It seems like there is a better way to do this. Any ideas?
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David Winsemius, MD
Alameda, CA, USA