Re: Union question

*To*: mathgroup at smc.vnet.net*Subject*: [mg13922] Re: [mg13889] Union question*From*: BobHanlon at aol.com*Date*: Mon, 7 Sep 1998 01:22:47 -0400*Sender*: owner-wri-mathgroup at wolfram.com

Garrett, See on-line help for Union and SameTest. data = Table[Random[], {10}] {0.51655,0.37473,0.877331,0.0649562,0.653698,0.114661,0.075878,0.0756202, 0.505527,0.341529} closeEnough[x_, y_] := Abs[x-y] < 10^-1 (* In your case use 10^-12 *) Union[data, SameTest->closeEnough] {0.0649562,0.341529,0.505527,0.653698,0.877331} Bob Hanlon In a message dated 9/6/98 7:18:34 AM, gas2y at node4.unix.virginia.edu wrote: >I'm trying to take a very long list of real numbers and use the Union >function on it to remove duplicates. The problem is that the real >numbers that I consider to be the same, differ after their 12th decimal >place. I have tried without sucess to use N and SetAccuracy functions >on each element of the list Before using the Union Function, but to no >Avail. Is there any quick way to take a long list, and remove >duplicate elements by comparing only the first n significant digets of >each element.