Re: Mma: 13 is not prime!
- To: mathgroup at smc.vnet.net
- Subject: [mg4634] Re: Mma: 13 is not prime!
- From: Harald Berndt <haraldb at nature.berkeley.edu>
- Date: Thu, 22 Aug 1996 03:54:52 -0400
- Organization: University of California Forest Products Lab
- Sender: owner-wri-mathgroup at wolfram.com
Felix Holderied wrote:
>
> Please help me:
>
> In[]:=
> PrimeQ[13]
> Out[]=
> True
>
> In[]:=
> PrimeQ[p] /.{p->13}
> Out[]=
> False
>
> WHY?
>
> Greetings, Felix
It's all in the evaluation order! Basically, you get the answer for
PrimeQ[p]
which is evaluated before the replacement takes place (and has of
course the result False). Try instead
In[93]:=
ReleaseHold[ Hold[PrimeQ[p]] /.{p->13} ]
Out[93]=
True
--
_______________________________________________________________
Harald Berndt University of California
Research Specialist Forest Products Laboratory
Phone: 510-215-4224 FAX:510-215-4299
_______________________________________________________________
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