Re: Need to reduce 2 lists so that only {x,y} pairs with same x remain

*To*: mathgroup at smc.vnet.net*Subject*: [mg24177] Re: Need to reduce 2 lists so that only {x,y} pairs with same x remain*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Wed, 28 Jun 2000 22:50:58 -0400 (EDT)*Organization*: Universitaet Leipzig*References*: <8jc73k$dg3@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

materialsscientist at my-deja.com wrote: > Hi, the function PairSelect[data1_, data2_] := Module[{lst}, lst = Intersection @@ Map[First , {data1, data2}, {2}]; Select[#, MemberQ[lst, First[#]] &] & /@ {data1, data2} ] return a list of {data1,data2} with common x values of both lists. Regards Jens > Hello, > > I have 2 lists of data: > > for example > data1={{1,1},{1.5,1.5},{2,2},{3,3},{4,4},{5,5}} > > data2={{1,2},{2,3},{3,4},{4,5},{6,7},{7,8}} > > I want to do a point by point comparision, so I > need to reduce both data1 and data2 so that > common x data in the {x,y} pairs for each list > remain. > > Thus the lists should look like this: > > data1={{1,1},{2,2},{3,3},{4,4}} > data2={{1,2},{2,3},{3,4},{4,5}} > > What function(s) would to something like this? > > Thanks, > > Chuck > > Sent via Deja.com http://www.deja.com/ > Before you buy.