Re: Apply function to parts of a list
- To: mathgroup at smc.vnet.net
- Subject: [mg86248] Re: [mg86224] Apply function to parts of a list
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Fri, 7 Mar 2008 02:24:54 -0500 (EST)
- Reply-to: hanlonr at cox.net
data = {{x1, y1}, {x2, y2}, {x3, y3}};
{2, 1} # & /@ data
{{2*x1, y1}, {2*x2, y2}, {2*x3, y3}}
data /. {x_, y_} -> {2 x, y}
{{2*x1, y1}, {2*x2, y2}, {2*x3, y3}}
Bob Hanlon
---- guerom00 <guerom00 at gmail.com> 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.
>