[Date Index] [Thread Index] [Author Index]

Re: More help on sorting out a large list

• To: mathgroup at smc.vnet.net
• Subject: [mg58382] Re: More help on sorting out a large list
• From: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>
• Date: Thu, 30 Jun 2005 04:37:18 -0400 (EDT)
• Organization: Uni Leipzig
• References: <d9t15f$j7b$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Hi,
try
Split[data, #1[[5]] == #2[[5]] && #1[[6]] == 
#2[[6]] &]

to group the data. But your posting is unclear 
what "take the average" mean. Is it the average 
over all columns ?

Regards

  Jens

"tornado78" <tornado78 at hotmail.com> schrieb im 
Newsbeitrag news:d9t15f$j7b$1 at smc.vnet.net...
> Ok here's a problem I've been trying to figure 
> out for awhile.  I have a large XYZ sorted 
> matrix and what i need is to look at two columns 
> x,y and and if it is a unique point keep the 
> row, if there are multiple rows with same x,y 
> pair i need to remove all of them and leave only 
> the middle Z row or the average of the middle 
> two Z rows
>
> for example
>
>             x  y  z
> {1, 6, 4, 8, 4, 5, 8, 3} drop
> {1, 3, 5, 8, 4, 5, 3, 3}--take
> {5, 3, 6, 8, 4, 5, 6, 3} drop
> {4, 5, 3, 4, 5, 6, 1, 0}drop
> {2, 5, 4, 3, 5, 6, 9, 1}\
> {1, 2, 5, 4, 5, 6, 7, 8} -take average
> {3, 5, 6, 3, 5, 6, 6, 4}drop
> {5, 3, 5, 2, 7, 8, 2, 5}----take
>
>
> thanks for any help
>