Re: Q: How to force an Equal[]
- Subject: [mg3359] Re: [mg3332] Q: How to force an Equal[]
- From: brucec (Bruce Carpenter)
- Date: 29 Feb 1996 11:25:06 -0600
- Approved: usenet@wri.com
- Distribution: local
- Newsgroups: wri.mathgroup
- Organization: Wolfram Research, Inc.
- Sender: daemon at wri.com
>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)
I believe you want to use y1 === y2, which is the infix form of SameQ[y1, y2].
Cheers,
Bruce Carpenter