Sorting with Infinity

• To: mathgroup at smc.vnet.net
• Subject: [mg23513] Sorting with Infinity
• From: Jack Goldberg <jackgold at math.lsa.umich.edu>
• Date: Tue, 16 May 2000 02:44:59 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

```Hi group;

I construct lists which may look like this

{7,-2,-Infinity,Infinity,1}

When this list is sorted by using Sort, I get

{-2,1,7,-Infinity,Infinity}

I would prefer, naturally,

{-Infinity,-2,1,7,Infinity}

This is easy to do if one doesn't care about elegance.  Without
spelling out the obvious details, here are a few kludges:

(1) Replace Infinity by 10^15, Sort  then switch back to Infinity.
(2) Use Append and Prepend after Sort and  deleting infinities.
(3) RotateRight after Sort and switch signs on infinities

Anyone got a "cute" solution say by using a sorting function or
perhaps some arcane command unknown to mere mortals?

Jack

```

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