Re: ReplaceAll and rules from a list v7.0

*To*: mathgroup at smc.vnet.net*Subject*: [mg104244] Re: ReplaceAll and rules from a list v7.0*From*: "Nasser M. Abbasi" <nma at 12000.org>*Date*: Sun, 25 Oct 2009 01:04:54 -0400 (EDT)*References*: <hbu7qi$7hn$1@smc.vnet.net>

"kristoph" <kristophs.post at web.de> wrote in message news:hbu7qi$7hn$1 at smc.vnet.net... > Hi, > > Suppose I have the equation > > x=a+b > > and the list > > l={{1,1},{2,2},{3,3}} > > How can I quickly assign the list to the above equation, that is, I > would like to get the following result > > {2,4,6} > > The first element of each sub-list should be assigned to a and the > second to b. > > Thanks in advance. > Kristoph > This is one of the problems there there is probably 10 ways to do in Mathematica. Here is one way, but I am sure there is a short way to do this. Map a replacement rule to the list. x = a + b; list = {{1, 1}, {2, 2}, {3, 3}}; (x /. {a -> #1[[1]], b -> #1[[2]]} & ) /@ list {2, 4, 6} --Nasser