Sort on vector component

*To*: mathgroup at smc.vnet.net*Subject*: [mg122006] Sort on vector component*From*: "Dr. Wolfgang Hintze" <weh at snafu.de>*Date*: Sat, 8 Oct 2011 05:36:18 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

Given a list u = {{2, 12, 7, 21}, {2, 48, 47, 97}, {4, 42, 41, 87}, {6, 8, 1, 15}, {6, 12, 9, 27}} How can I sort it with respect to a given index position i=(1, ..., 4)? For i=1 it is simply Sort, for the last one I could use In[75]:= Reverse /@ Sort[Reverse /@ u] Out[75]= {{6, 8, 1, 15}, {2, 12, 7, 21}, {6, 12, 9, 27}, {4, 42, 41, 87}, {2, 48, 47, 97}} I don't want to go in the details of defining lexicographical order but just obtain a sorting as described above. Any ideas? Thanks in advance. Wolfgang

**Follow-Ups**:**RE: Sort on vector component***From:*Richard Hofler <rhofler@bus.ucf.edu>

**Re: Sort on vector component***From:*Adriano Pascoletti <adriano.pascoletti@uniud.it>

**Re: Sort on vector component***From:*DrMajorBob <btreat1@austin.rr.com>