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. >