Re: Sort problem

*To*: mathgroup at smc.vnet.net*Subject*: [mg81725] Re: Sort problem*From*: Aranthon <a.dwarf at gmail.com>*Date*: Tue, 2 Oct 2007 05:39:46 -0400 (EDT)*References*: <fdqd33$n6m$1@smc.vnet.net>

On Oct 1, 5:02 am, Donald DuBois <don... at comcast.net> wrote: > Hello, > > This Sort works > > In[32]:= Sort[{r, a, x}] > > Out[32]= {a, r, x} > > but this one doesn't: > > In[33]:= Sort[{{r, 2}, {a, 3}, {x, 4}}, #1[[1]] < #2[[1]] &] > > Out[33]= {{r, 2}, {a, 3}, {x, 4}} > > What am I doing wrong? > > Don The problem is that since you're sorting symbols, Less is the wrong ordering function. If you use OrderedQ[{First[#1],First[#2]}]&, it'll work (in fact, you can get away with just OrderedQ[{#1,#2}]& ) Greg