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
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