Re: Dot or Inner ... but not quite
- To: mathgroup at smc.vnet.net
- Subject: [mg79634] Re: [mg79622] Dot or Inner ... but not quite
- From: Sseziwa Mukasa <mukasa at jeol.com>
- Date: Wed, 1 Aug 2007 04:50:46 -0400 (EDT)
- References: <200707311013.GAA21053@smc.vnet.net>
On Jul 31, 2007, at 6:13 AM, Diamond, Mark wrote:
> I have two equi-length lists, the first of number, the second of
> (equi-length) lists of numbers , such as
>
> l1={1,4,3};
> l2={{1,7},{1,9},{5,2}};
>
> I want to produce 1*{1,7}+4*{1,9}+3*{5,2}
>
> It looks so close to Inner that I thought I could use it in some
> form, but I
> have ended up using
>
> (#[[1]]*#[[2]])& /@ Transpose[{l1,l2}]
>
> Is there a better way using one of the builtin functions with which
> I am
> unfamiliar?
You could just write what you want explicitly:
Plus@@(l1 l2)
or use Inner:
Inner[Times,l1,l2,Plus]
Regards,
Ssezi