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