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MathGroup Archive 1997

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Re: Partition List

  • To: mathgroup at smc.vnet.net
  • Subject: [mg8463] Re: Partition List
  • From: crose at c2.telstra-mm.net.au (Colin Rose)
  • Date: Tue, 2 Sep 1997 16:14:57 -0400
  • Organization: Theoretical Research Institute
  • Sender: owner-wri-mathgroup at wolfram.com

So many partition lists :)

While Split[m, #2 != 10 &] seems much neater than the other
functional solutions posted, it is alas also much slower.

For instance:

   m = Table[Random[Integer, {1, 50}], {100000}];


Timing[p = Flatten[Position[m, 10]]; 
   MapThread[Take[m, {#1, #2}]&, {Prepend[p, 1], Append[p-1, Length[m]]}]; ]

Out[42]=   {0.39*Second, Null}


vs

Split[m,#2!=10&]; // Timing

Out[44]=   {2.03333 Second,Null}



Cheers

Colin

-- 
Colin Rose 
tr(I) - Theoretical Research Institute
______________________________________
crose at c2.telstra-mm.net.au
http://www.usyd.edu.au/su/tri/


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