Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2000
*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 2000

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

Search the Archive

Re: functional routine for {a, b, c, ...} -> {a - b, b - c, c - ...}

  • To: mathgroup at smc.vnet.net
  • Subject: [mg24920] Re: [mg24892] functional routine for {a, b, c, ...} -> {a - b, b - c, c - ...}
  • From: Rob Pratt <rpratt at email.unc.edu>
  • Date: Sun, 20 Aug 2000 01:35:11 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

Not functional programming, but it's short, natural, and fast:

Drop[lst - RotateLeft[lst], -1]

Rob Pratt
Department of Operations Research
The University of North Carolina at Chapel Hill

rpratt at email.unc.edu

http://www.unc.edu/~rpratt/

On Sat, 19 Aug 2000 Maarten.vanderBurgt at icos.be wrote:

> Hallo,
> 
>  element.
> I found two ways for doing this:
> 
> lst = {a, b, c, d, e, f, g, h};
> 
> Table[lst[[i]] - lst[[i + 1]], {i, 1, Length[lst] - 1}]
> {a - b, b - c, c - d, d - e, e - f, f - g, g - h}
> 
> ListCorrelate[{1, -1}, lst]
> {a - b, b - c, c - d, d - e, e - f, f - g, g - h}
> 
> The first method is rather clumsy and the 2nd one is quite short, but not
> really obvious.
> Initally I was looking for a functional programming style routine.
> Something like: (#[[i]]-#[[i-1]])&/@lst.
> Who can tell me how to do this in a functional programming style?
> 
> Thanks
> 
> Maarten van der Burgt
> Leuven, Belgium
> 
> 
> 
> 



  • Prev by Date: Re: How to get two values from a file into two lists?
  • Next by Date: Re: functional routine for {a, b, c, ...} -> {a - b, b - c, c - ...}
  • Previous by thread: Re: functional routine for {a, b, c, ...} -> {a - b, b - c, c - ...}
  • Next by thread: Re: functional routine for {a, b, c, ...} -> {a - b, b - c, c - ...}