Re: sum with lists
- To: mathgroup at smc.vnet.net
- Subject: [mg40593] Re: [mg40534] sum with lists
- From: Amit Gandhi <akgandhi at uchicago.edu>
- Date: Thu, 10 Apr 2003 03:44:19 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
one way:
Form a new list x = Table[d[[i,1]*d[[i,3]], {i, 1, n/2}]
and then use Apply[Plus,x]
Amit
On Wednesday, April 9, 2003, at 07:26 PM, 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
>