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Re: I don't know how to ....

  • To: mathgroup at
  • Subject: [mg2425] Re: I don't know how to ....
  • From: rubin at (Paul A. Rubin)
  • Date: Sun, 5 Nov 1995 16:06:51 -0500
  • Organization: Michigan State University

In article <471hgv$gb3 at>,
   bientin at (Paolo Bientinesi) wrote:
->Hi all,
->here's my problem:
->I need  a function that takea as input a list of pairs;
->the first element of every pair is a list, the second one is an integer;
->I want the function to calculate thhe
->biggest integer and to give as output the corresponding list.
->I didn't succeeded.
->Paul DJ a
In[1]:=  Clear[f];
         f[ x:{{_List, _Integer}..} ] := Sort[ Reverse /@ x ][[-1, 2]]
In[2]:=  xx = {{{a,b,c}, 5}, {{d,e}, -3}, {{f,g,h,i}, 7}};
In[3]:=  f[xx]
Out[3]=  {f, g, h, i}

This is a trifle inefficient if your list is long, since it sorts the 
entire list (rather than just isolating the largest integer).  For long 
lists, a partial bubble sort might be better.  Also, I've ignored the 
question of resolving ties for largest integer; you might prefer to print 
all lists whose integers are tied (assuming ties can occur in your 

Paul Rubin

* Paul A. Rubin                                  Phone: (517) 432-3509   *
* Department of Management                       Fax:   (517) 432-1111   *
* Eli Broad Graduate School of Management        Net:   RUBIN at MSU.EDU    *
* Michigan State University                                              *
* East Lansing, MI  48824-1122  (USA)                                    *
Mathematicians are like Frenchmen:  whenever you say something to them,
they translate it into their own language, and at once it is something
entirely different.                                    J. W. v. GOETHE

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