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Re: help for time series basic operations

  • To: mathgroup at smc.vnet.net
  • Subject: [mg46080] Re: [mg46046] help for time series basic operations
  • From: János Löbb <janos.lobb at yale.edu>
  • Date: Thu, 5 Feb 2004 04:02:59 -0500 (EST)
  • References: <200402032320.SAA28930@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

My newbee approach:

a = {a1, a2, a3, a4, a5, a6, a7}
Partition[a, 2, 1] /. {x_, y_} -> (y - x)
{-a1 + a2, -a2 + a3, -a3 + a4, -a4 + a5, -a5 + a6, -a6 + a7}

János


On Feb 3, 2004, at 6:20 PM, paolo wrote:

> I am a quantitative analyst and for the first time i am using 
> Mathematica. So, I
> am sorry if my question seem "very easy (almost stupid)" but 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]
>
> Thanks
>
> Paolo Tarpanelli
>
>
-------------------------------------------------
clear perl code is better than unclear awk code; but NOTHING comes 
close to unclear perl code
http://www.faqs.org/faqs/computer-lang/awk/faq/


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