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Re: Riddle with Ordering

• To: mathgroup at smc.vnet.net
• Subject: [mg77939] Re: Riddle with Ordering
• From: Ray Koopman <koopman at sfu.ca>
• Date: Wed, 20 Jun 2007 05:30:45 -0400 (EDT)
• References: <f58dbg$8gi$1@smc.vnet.net>

On Jun 19, 4:06 am, nazdro... at gmail.com wrote:
> Just a gem I discovered with Ordering[ ].
>
> Anyone have an idea what
>
> SomeArrayWithUniqueReals // Ordering // Ordering
>
> does?
>
> I like this, especially the double use of Ordering. Answer tomorrow.

   Ordering@Ordering@x

gives the ranks of the elements of x, with ties broken according to
position in x. To give tied values their average rank, use

  (Ordering@Ordering@x + Reverse@Ordering@Ordering@Reverse@x)/2