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Re: SortBy won't order irrationals

  • To: mathgroup at smc.vnet.net
  • Subject: [mg124102] Re: [mg124028] SortBy won't order irrationals
  • From: Christopher Young <cy56 at comcast.net>
  • Date: Mon, 9 Jan 2012 03:16:07 -0500 (EST)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
  • References: <201201060916.EAA26862@smc.vnet.net> <AE02F0F7-A101-45CD-B304-A19626EBAE43@mimuw.edu.pl>

OK, but that's not the behavior I'd expect, and it's something that has 
to be watched out for constantly. For example, if we use SortBy, I think 
that after all the functions have been applied to the list, we're stuck 
with this sorting  by complexity of expression unless we remember to 
apply N to every element of the list together with each of our other 
functions.

On Jan 6, 2012, at 5:46 PM, Andrzej Kozlowski wrote:

> Numeric symbols like Sqrt[2],Pi,E  etc.  etc are not sorted by their 
value but in the same way as all other symbols. Compare:
>
> Sort[{Pi, 4, Sqrt[2], 2, 3*E}]
>
> {2, 4, Sqrt[2], 3*E, Pi}
>
> with
>
> Sort[{Pi, 4, Sqrt[2], 2, 3*E}, Less]
>
> {Sqrt[2], 2, Pi, 4, 3*E}
>
>
> Note also that you can use Sort with a custom ordering function.
>
>
> Andrzej Kozlowski






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