Re: Replacing elements in a list

*To*: mathgroup at smc.vnet.net*Subject*: [mg90105] Re: [mg90092] Replacing elements in a list*From*: Bob Hanlon <hanlonr at cox.net>*Date*: Sun, 29 Jun 2008 05:34:55 -0400 (EDT)*Reply-to*: hanlonr at cox.net

pairs = {{1, 2}, {3, 4}, {1, {1, 2}}}; elem = Union[Flatten[pairs, 1]] {1,2,3,4,{1,2}} pairs /. {x_, y_List} :> {x, Position[elem, y][[1, 1]]} {{1, 2}, {3, 4}, {1, 5}} Bob Hanlon ---- yedidel at gmail.com wrote: > Hello, > > I have a list of pairs that looks like this: > > {{1,2},{3,4},{1,{1,2}}} > > Each pair element can be a pair by itself. > > I have another list which lists all elements possible: > {1,2,3,4,{1,2}} > > Now I want to create a list of rules that will take the element list > and give it a running number ({1,2} will be 5 in this example) > > after that I want to apply those rules to the pair list BUT that will > do it only from the second level down. This means that the final > result should be: > > {{1,2},{3,4},{1,5}} > without the first pair {1,2} changing to 5 because it is a pair and > not an element. > >