Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2002
*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 2002

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

Search the Archive

Re: Operating on every k-th element of list?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg37124] Re: [mg37080] Operating on every k-th element of list?
  • From: Bill Rowe <listuser at earthlink.net>
  • Date: Thu, 10 Oct 2002 03:21:18 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

On 10/8/02 at 7:17 AM, siegman at stanford.edu (AES) wrote:

>I want to apply a function to every  k-th  element of a long list and
>add the result to the  k+1  element.
>
>[Actually  k = 3  and I just want to multiply  myList[[k]]  by a
>constant (independent of k)  and add the result to  myList[[k+1]]  for
>every value of  k  that's divisible by 3.]

If I understand what you are trying to do correctly, the following should work

(f[#[[1]]+#[[2]])&/@Partition[Drop[list,k-1],2,k]

Here f is the function you want applied to the k-th element


  • Prev by Date: Print[]ing Text and a Table
  • Next by Date: Phase Portraits
  • Previous by thread: Re: Operating on every k-th element of list?
  • Next by thread: Successive Approximation