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MathGroup Archive 2004

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Partition of multi dimension list

  • To: mathgroup at
  • Subject: [mg52736] Partition of multi dimension list
  • From: "Bruyndonckx P." <pbruynd at>
  • Date: Sat, 11 Dec 2004 05:21:51 -0500 (EST)
  • Sender: owner-wri-mathgroup at

I have a list of about 5 million items.  Each item is a list of 7 integer numbers (hence a 5000000x7 array).  I want to partition this array on the values of two 
numbers in each item.  The third number (out of seven) goes from 0 to 63 and the fifth number is either 0 or 1.  So I want to end up with 64*2 partitions.  The 
fastest solution I have found up to now to do this on the list 'c' is Flatten[CategoryLists[c, {_}, {_}, Range[64] - 1, {_}, {0,1}, {_}, {_}][[1, 1]], 4].

Since I am not a real expert in Mathematica, can anybody suggest me a possible faster and/or cleaner  way to achieve this.



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