Re: sum with lists
- To: mathgroup at smc.vnet.net
- Subject: [mg40598] Re: [mg40534] sum with lists
- From: SONKOLY Pal <phaul at inf.elte.hu>
- Date: Fri, 11 Apr 2003 01:59:07 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
This does exactly what you want.
Plus @@ ((d[[#-1]][[1]] * d[[#-1]][[3]])& /@ Range[11])
Phaul
On Wed, 9 Apr 2003, Nathan Moore wrote:
> Another list question. Suppose that I have the list
> d={
> {x0,y0,z0},
> {x1,y1,z1},
> {x2,y2,z1},
> ...
> {xn,yn,zn}}
>
> and now I'd like to calculate the sum,
> Sum[x[i]*z[i],{i,0,n/2}]
>
> I tried
> Sum[d[[i, 1]]*d[[i, 3]], {i, 0, 10}]
> with little success
>
> thanks,
>
> Nathan Moore,
> University of Minnesota Physics
>
>