Re: help for time series basic operations

*To*: mathgroup at smc.vnet.net*Subject*: [mg46057] Re: help for time series basic operations*From*: bobhanlon at aol.com (Bob Hanlon)*Date*: Tue, 3 Feb 2004 22:19:09 -0500 (EST)*References*: <bvpaq9$scp$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Here are some of the ways: al[n_] := Table[ToExpression["a"<>ToString[k]],{k,n}]; a = al[5]; b = Rest[a-RotateRight[a]] {a2-a1,a3-a2,a4-a3,a5-a4} b==Drop[RotateLeft[a]-a,-1] True b==Rest[a]-Drop[a,-1] True b==ListCorrelate[{-1,1}, a] True b==ListConvolve[{1,-1}, a] True Bob Hanlon In article <bvpaq9$scp$1 at smc.vnet.net>, "paolo" <tarpanelli at libero.it> wrote: << i need some helps to begin to understand Mathematica I have a time series a:=[a_1,a_2,a_3,a_4,...a_n] how can i do to subtract each element for the previous one?: b:=[a_2 - a_1, a_3 - a_2, a_4 - a_3,.....,a_n - a_n-1] >><BR><BR>