R help - Jul 2004 - computing differences between consecutive vectorelements

well, sure diff() does it
thanks alot

Thomas
> -----Message d'origine-----
> De: Liaw, Andy [mailto:andy_liaw at merck.com]
> Date: mardi 27 juillet 2004 16:50
> ??: 'Dewez Thomas'; 'r-help at stat.math.ethz.ch'
> Objet: RE: [R] computing differences between consecutive 
> vectorelements
> 
> 
> Not exactly sure what you want, but seems like you can sort 
> the data frame
> by `t', then do diff() on the x, y, and z columns.
> 
> Andy
> 
> > From: Dewez Thomas
> > 
> > Dear R-users,
> > 
> > I am a newbie to R so please excuse this naive question for 
> > which I couldn't
> > seem to find online answers.
> > 
> > I have this data frame containing a series of locations through time
> > (x,y,z,t). I would like to compute the difference in x, y and 
> > z between t-1
> > and t.
> > 
> > Sounds easy enough, but how on earth does one loop through 
> > vector elements
> > and compute this difference?
> > 
> > Thanks
> > 
> > Thomas
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