Re: ReplaceAll and rules from a list v7.0

*To*: mathgroup at smc.vnet.net*Subject*: [mg104261] Re: [mg104227] ReplaceAll and rules from a list v7.0*From*: Bob Hanlon <hanlonr at cox.net>*Date*: Sun, 25 Oct 2009 01:08:05 -0400 (EDT)*Reply-to*: hanlonr at cox.net

l = {{1, 1}, {2, 2}, {3, 3}}; Total /@ l {2,4,6} Plus @@@ l {2,4,6} Plus @@ # & /@ l {2,4,6} #[[1]] + #[[2]] & /@ l {2,4,6} f[a_, b_] := a + b f @@@ l {2,4,6} a + b /. Thread[{a, b} -> #] & /@ l {2,4,6} eqn = x == a + b; eqn[[2]] /. Thread[{a, b} -> #] & /@ l {2,4,6} eqn[[2]] /. Thread /@ (Variables[eqn[[2]]] -> # & /@ l) {2,4,6} Bob Hanlon ---- kristoph <kristophs.post at web.de> wrote: ============= 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