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Re: Apply function to parts of a list

  • To: mathgroup at smc.vnet.net
  • Subject: [mg86285] Re: [mg86224] Apply function to parts of a list
  • From: Curtis Osterhoudt <cfo at lanl.gov>
  • Date: Fri, 7 Mar 2008 02:31:51 -0500 (EST)
  • Organization: LANL
  • References: <200803060759.CAA29253@smc.vnet.net>
  • Reply-to: cfo at lanl.gov

   You could try using replacements on the second of each pair: 

         data/.{a_, b_}->{a, 2b}

        Or termwise multiplication:

         #*{1,2}&/@data

       

On Thursday 06 March 2008 00:59:51 guerom00 wrote:
> Hi all,
>
> Very often, I find myself having datas to plot of this form :
>
> data={{x1,y1},{x2,y2},{x3,y3}...{xn,yn}}
>
> So, very conventional : a list of abscissa and ordinate. Now, let's say I
> want to multiply by 2 all my ascissa. Right now, I write :
>
> MapAt[2*#&,data,Table[{i,1},{i,1,Length[data]}]]
>
> It's OK but I isn't there another way to achieve this as I find this rather
> "involved" for such a simple thing ?
>
> Thanks in advance.



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