Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2004
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2004

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Partitioning a list into unequal partitions

  • To: mathgroup at smc.vnet.net
  • Subject: [mg47492] Re: Partitioning a list into unequal partitions
  • From: drbob at bigfoot.com (Bobby R. Treat)
  • Date: Wed, 14 Apr 2004 07:16:45 -0400 (EDT)
  • References: <c5gfdp$an0$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

There are many ways, but here's my favorite:

triangleRule = z : {x___List, 
    y_List} /; Length[y] > Length@z :> {x, Take[y,
         Length@z], Drop[y, Length@z]};
triangularPartition[x_List] := {x} //. triangleRule

Here's a test, for lengths from 1 to 20. Note that I leave the extras
in a list at the end when the length isn't "correct".

Composition[triangularPartition, Range] /@ Range@20 // ColumnForm

(output suppressed)

Bobby

"DIAMOND Mark R." <dot at dot.dot> wrote in message news:<c5gfdp$an0$1 at smc.vnet.net>...
> Could someone please show me a simple (non-procedural) way of partitioning a
> list into 1,2,3 ... n disjoint sublists, where the length of the list is
> guaranteed to be correct (i.e. n*(n+1)/2)
> 
> I can't see a way, and yet I'm sure there *must* be a one-liner using Fold.
> 
> Cheers
> 
> Mark R. Diamond


  • Prev by Date: RE: Format Style
  • Next by Date: Re: InLine Formatting
  • Previous by thread: Re: Partitioning a list into unequal partitions
  • Next by thread: Re: Partitioning a list into unequal partitions