Re: RE: nth differences

*To*: mathgroup at smc.vnet.net*Subject*: [mg39887] Re: [mg39862] RE: [mg39852] nth differences*From*: Dr Bob <drbob at bigfoot.com>*Date*: Sun, 9 Mar 2003 18:39:27 -0500 (EST)*References*: <200303091027.FAA07451@smc.vnet.net>*Reply-to*: drbob at bigfoot.com*Sender*: owner-wri-mathgroup at wolfram.com

Try this: differences[a_List] := NestList[ Subtract @@@ Partition[#, 2, 1] &, -a, Length@a - 1] s = {1, 2, 5, 7, 8, 9}; differences@s // TableForm Bobby On Sun, 9 Mar 2003 05:27:13 -0500 (EST), Harvey P. Dale <hpd1 at nyu.edu> wrote: > > Zachary: > After entering the list of k integers, evaluate the following: > #[[2]]-#[[1]]&/@Partition[%,2,1] > Then you can evaluate exactly the same expression again, and again, > until the nth difference is a single number. The easiest way to do that > is to type <ctrl>+L, which automatically inserts, for evaluation, the > prior input. > Hope that helps. > Best, > Harvey > > -----Original Message----- > From: Zachary Turner [mailto:_NOzturnerSPAM_ at cyberonic.com] To: mathgroup at smc.vnet.net > To: mathgroup at smc.vnet.net > Subject: [mg39887] [mg39862] [mg39852] nth differences > > Say I have a list of k integers and I want to produce a list containing > the > first differences? For example, given {1, 2, 5, 7, 8, 9} the first > differences are {1, 3, 2, 1, 1}, and the second differences are {2, -1, > -1, > 0}, the third are {-3, 0, 1}, etc > > > > -- majort at cox-internet.com Bobby R. Treat

**References**:**RE: nth differences***From:*"Harvey P. Dale" <hpd1@nyu.edu>