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Re: A NewBie Question

  • To: mathgroup at smc.vnet.net
  • Subject: [mg53612] Re: [mg53582] A NewBie Question
  • From: Andrzej Kozlowski <akozlowski at gmail.com>
  • Date: Thu, 20 Jan 2005 03:47:53 -0500 (EST)
  • References: <200501190659.BAA06806@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

On 19 Jan 2005, at 07:59, Zhe Hu wrote:

> Is there a way to take parts of a list as follows:
>
> takeParts[{a,b,c,d,e,f,g,h,i}, {2,3,4}]
>
> {{a,b}, {c,d,e}, {f,g,h,i}}
>
> A tedious way might be transforming {2, 3, 4} into {{1,2}, {3,5}, {6,
> 9}} (by Fold) and then Part/@ onto it. Is there a simpler way to do
> it?
>
> Thanks,
> Hu Zhe
>

Simplicity is, to some extend at least, in the eye of the beholder, but 
I suppose this is not as simple as what you had in mind:

Reap[Fold[(Sow[Take[#1, #2]]; Drop[#1, #2]) & , ls,
     Range[2, 4]]][[2,1]]

{{a, b}, {c, d, e}, {f, g, h, i}}


Andrzej Kozlowski
Chiba, Japan
http://www.akikoz.net/~andrzej/
http://www.mimuw.edu.pl/~akoz/


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