Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
1993
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 1993

[Date Index] [Thread Index] [Author Index]

Search the Archive

re:sort pairs

  • To: mathgroup at yoda.physics.unc.edu
  • Subject: re:sort pairs
  • From: wmm at chem.wayne.edu (Martin McClain)
  • Date: Mon, 15 Nov 93 10:55:13 EST

> How can I sort pairs of values -- basing the sort on the first value
> and then break ties on the second value in the pair.
> 
> Let's say I have n pairs on numbers in the following matrix
> 
> data = { {x1,y1}, .....{xi, yi}, .....{xn,yn} }
> 
> Using the Sort function in Mma, I can easily sort on the xi values, but
> how can I do the secondary sort on the yi values??

I think this happens automatically.  I just tried

       Sort[ {{5,9},{2,7},{5,6},{7,1},{5,2}}]

with many permutations of the interior pairs, and the answer always comes 
out as
        {{2,7},{5,2},{5,6},{5,9},{7,1}}.

Isn't this exactly what you want?
Regards- Martin






  • Prev by Date: Re: Strange answer
  • Next by Date: cyclotomics
  • Previous by thread: sort pairs
  • Next by thread: courses