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Re: Partition a list into sublists of unequal size

  • To: mathgroup at smc.vnet.net
  • Subject: [mg83940] Re: Partition a list into sublists of unequal size
  • From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
  • Date: Wed, 5 Dec 2007 07:08:02 -0500 (EST)
  • Organization: Uni Leipzig
  • References: <fj37cv$hq0$1@smc.vnet.net>
  • Reply-to: kuska at informatik.uni-leipzig.de

Hi,

list = {1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0};
test = Array[a, {16}];

First /@ Rest[
   FoldList[{Take[test, {Min[#1[[2]] + 1, #2], #2}], #2} &, {1, 1},
    Flatten@Position[list, 1]]]

may do that.

Regards
   Jens

antf wrote:
> Hello,
> 
> I have a list that looks like the following:
> 
> list={1,0,0,1,0,0,1,1,0,1,0,0,0,0,1,0}
> 
> I then find the positions of the 1s in the list:
> 
> positions = Flatten@Position[list,1]
> 
> {1,4,7,8,10,15}
> 
> I then want to partition a third list into sublists so that the first
> sublist is from index 1;;1, the second sublist is from index 2;;4, the
> third sublist is from index 5;;7, the fourth sublist is just element
> 8, etc.
> 
> Currently, I use Partition on the positions sublist with overlap as
> in:
> 
> Partition[Join[{1},positions],2,1]
> 
> {{1,1},{1,4},{4,7},{7,8},{8,10},{10,15}}
> 
> I then use this list to partition the target list by Mapping Take to
> each element of this list and adjusting the first index appropriately.
> 
> I am sure there must be a simpler way to do this.  Can anyone tell me
> how to do this operation?
> 
> Thanks,
> Anthony
> 


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