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

*To*: mathgroup at smc.vnet.net*Subject*: [mg24189] Re: Need to reduce 2 lists so that only {x,y} pairs with same x remain*From*: dkeith at sarif.com*Date*: Wed, 28 Jun 2000 22:51:09 -0400 (EDT)*References*: <8jc73k$dg3@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Hi Chuck, This function accepts the two lists and returns a list of two lists whose x values are contained in the set intersection of the x values of the two lists. commonX[list1_, list2_] := Select[#, MemberQ[Intersection[list1 [[All,1]], list2[[All, 1]]], #[[1]]] &] & /@ {list1, list2} In article <8jc73k$dg3 at smc.vnet.net>, materialsscientist at my-deja.com wrote: > 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. > > Sent via Deja.com http://www.deja.com/ Before you buy.