Services & Resources / Wolfram Forums
MathGroup Archive
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 1992

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

Search the Archive

ReplaceAll feature

  • To: mathgroup at
  • Subject: ReplaceAll feature
  • From: Pekka.Janhunen at
  • Date: Wed, 7 Oct 1992 09:35:29 -0800

In the following, why is Out[1] different from Out[2] and Out[3]:

Mathematica 2.0 for SGI Iris
Copyright 1988-91 Wolfram Research, Inc.
 -- Terminal graphics initialized --

In[1]:= (a+b+c+d)/.{a+b->x,c+d->y}

Out[1]= c + d + x

In[2]:= (a+b+c+d)/.a+b->x/.c+d->y

Out[2]= x + y

In[3]:= (a+b+c+d)//.{a+b->x,c+d->y}

Out[3]= x + y

I guess it has something to do with Flat. This is not a big problem, but IF
it can be easily fixed, it should be fixed. But maybe there are some "deep"
reasons why it behaves like this ?
  Pekka Janhunen                    tel (+358) 0 1929 535
  Finnish Meterological Institute   fax (+358) 0 1929 539
  Geophysics Department             tlx 124436 EFKL SF
  P.O.BOX 503, SF-00101 Helsinki
  Internet    : Pekka.Janhunen at
  SPAN & NSI  : 22104::pouta::Pekka.Janhunen     
  EARN/Bitnet : at fingate
  x.400       : /C=fi/ADMD=Mailnet/PRMD=IL/SUR=Janhunen/GIV=Pekka/    

  • Prev by Date: Re: Mathematica Problem
  • Next by Date: Displaying real numbers
  • Previous by thread: Re: Clipping ParametricPlot3D
  • Next by thread: Re: ReplaceAll feature