Re: Ordering function weird?

*To*: mathgroup at smc.vnet.net*Subject*: [mg82671] Re: Ordering function weird?*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Sun, 28 Oct 2007 03:58:30 -0500 (EST)*References*: <ffv29v$aph$1@smc.vnet.net>

Hi, (y[[#]] & /@ Ordering[y]) - Sort[y] may help you. Otherwise read the Help text for Ordering is say "Ordering[list] gives the positions in list at which each successive element of Sort[list] appears. " Regards Jens Claus wrote: > Hi, > say I've got two sets of number, x and y, which I want to rank. See the > example below. I totally expect and want the result of Ordering[x]. But > I neiter understand nor expect the result of Ordering[y]. Both Sort[x] > and Sort[y] are ok. > Can anybody explain to me Ordering[y]? > Thanks, > Claus > > > In[3]:= x = {1, 2, 3, 6, 10, 3, 4} > y = {1, 2, 7, 8, 9, 1, 2} > > Out[3]= {1, 2, 3, 6, 10, 3, 4} > > Out[4]= {1, 2, 7, 8, 9, 1, 2} > > In[5]:= Sort[x] > Sort[y] > > Out[5]= {1, 2, 3, 3, 4, 6, 10} > > Out[6]= {1, 1, 2, 2, 7, 8, 9} > > In[7]:= Ordering[x] > Ordering[y] > > Out[7]= {1, 2, 3, 6, 7, 4, 5} > > Out[8]= {1, 6, 2, 7, 3, 4, 5} >