Re: array_reverse() - Mailing list pgsql-general

From Sam Mason
Subject Re: array_reverse()
Date
Msg-id 20091102145159.GH5407@samason.me.uk
Whole thread Raw
In response to Re: array_reverse()  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: array_reverse()  (Merlin Moncure <mmoncure@gmail.com>)
Re: array_reverse()  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
On Mon, Nov 02, 2009 at 09:20:38AM -0500, Tom Lane wrote:
> Craig Ringer <craig@postnewspapers.com.au> writes:
> > Before I go ahead and try to write a decent quality version: is there
> > any chance an array_reverse() function (in C) would be accepted into Pg
> > mainline?
>
> What would it mean for a multi-dimensional array?

Rotating the array by 180 degrees in every dimension would give the same
answer for 1-dimensional arrays and give sensible answers for higher
dimensional arrays.  For example:

  1,2,3   ==  3,2,1

  [1 2 3     [9 8 7
   4 5 6  ==  6 5 4
   7 8 9]     3 2 1]

I think higher dimensionality would work, it's just a bit fiddly to
draw.

--
  Sam  http://samason.me.uk/

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