Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
1996
*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 1996

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

Search the Archive

Re: Q: How to force an Equal[]

  • To: mathgroup at smc.vnet.net
  • Subject: [mg3358] Re: Q: How to force an Equal[]
  • From: Johan Gunnarsson <johan at isy.liu.se>
  • Date: Thu, 29 Feb 1996 03:26:05 -0500
  • Organization: Linkoping University, Dept. of EE, Division of Automatic Control
  • Sender: owner-wri-mathgroup at wolfram.com

Gerd Lanfermann wrote:
> 
> Hi there,
> 
> this should be a nice relaxing one. How can I force Mma to evaluate
> the equal expression, regardless of what values Word or Number
> stand for. I just want a false in the second case (y1==y2).
> 
> In[]:=
> x1={car, nose, 2334.34};
> x2={dummy, 3.1415, 8};
> x3={eye,345,567};
> 
> In[]:=
> y1=Map[Head,x1]//.{Symbol->Word,Integer->Number, Real->Number}
> y2=Map[Head,x2]//.{Symbol->Word,Integer->Number, Real->Number}
> y3=Map[Head,x3]//.{Symbol->Word,Integer->Number, Real->Number}
> 
> Out[]:=
> {Word, Word, Number}
> {Word, Number, Number}
> {Word, Number, Number}
> 
> Here we go:
> 
> y2==y3
> 
> gives me as desired
> True
> 
> But this guy just returns the expressions:
> y1==y2
> 
> {Word, Word, Number} == {Word, Number, Number}
> 
> I would like to see a False here.It works when I do
> {Symbol->"Word", ...}, converting it to Strings. But I wouldn't
> call that a nice style of writing inMma.
> 
> Thanks
> Gerd
> 
> Gerd Lanfermann
> 840 N.Taylor
> St.Louis, Mo. 63122
> USA
> phone: (314) / 822 4518
> email: s997826 at umslvma.umsl.edu          (University of Missouri, St.Louis)
>        lanfer at sirius.physik.fu-berlin.de (Freie Universitaet Berlin)

Try
	y1===y2
instead.
-- 
_____________________________________________________
		Johan Gunnarsson             
     |    	Division of Automatic Control
    /|\   	Dept. of EE, Linkoping University
    \|/   	S-581 83 Linkoping, Sweden
    /|\   	Tel: 	+46 13 282913     
   / | \  	Fax: 	+46 13 282622     	
 ()  |  ()	Email: 	johan at isy.liu.se
		WWW:	http://control.isy.liu.se/~johan

==== [MESSAGE SEPARATOR] ====


  • Prev by Date: Solving sets of differential equations -- this should be easy...
  • Next by Date: Re: Q: How to force an Equal[]
  • Previous by thread: Re: Q: How to force an Equal[]
  • Next by thread: Re: Q: How to force an Equal[]