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Re: split a list

• To: mathgroup at smc.vnet.net
• Subject: [mg40552] Re: [mg40515] split a list
• From: Gary.Anderson at frb.gov
• Date: Thu, 10 Apr 2003 03:36:40 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

roberto,

how about
u=Select[r,#<m&];v=Select[r,#>m&]  but what about ==?
alternatively,
v=Complement[r,u=Select[r,#<m&]];



                                                                                                                 
                    Roberto                                                                                      
                    Brambilla            To:     mathgroup at smc.vnet.net                                          
                    <rlbrambilla@        cc:                                                                     
                    cesi.it>             Subject: [mg40552]     [mg40515] split a list                                     
                                                                                                                 
                    04/09/03                                                                                     
                    01:30 AM                                                                                     
                                                                                                                 
                                                                                                                 




Hi,

I have a list (very long, thousands, and unsorted) of numbers r={n1,n2...}
and for a given a number m  I want to split it in the two sublists
(unsorted, same order) u={elements<m], v={elements>m}.
Now I use this *old-style*  method:

u = v = {};
For[i = 1, i <= Length[r], i++,
  tmp = r[[i]];
  If[tmp > m , AppendTo[u, tmp], AppendTo[v, tmp]];
  ]

Any suggestion for a more efficient (and elegant) method?
Also oneliners are well accepted.

Many thanks, Roberto

Roberto Brambilla
CESI
Via Rubattino 54
20134 Milano
tel +39.02.2125.5875
fax +39.02.2125.5492
rlbrambilla at cesi.it

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