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}
>