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Re: Re: Re: Types in Mathematica thread

  • To: mathgroup at
  • Subject: [mg62884] Re: [mg62851] Re: Re: Types in Mathematica thread
  • From: Andrzej Kozlowski <akoz at>
  • Date: Thu, 8 Dec 2005 00:04:10 -0500 (EST)
  • References: <> <dn3fos$7l2$> <>
  • Sender: owner-wri-mathgroup at

On 7 Dec 2005, at 13:10, albert wrote:

> Hi,
>> The discussion was not about testing whether something is a real
>> number or not (in the mathematical sense). This you test with Element
>> [something, Reals]. The discussion was about "types". Please note the
>> title of the thread to which you have just contributed, or even
>> better rerad the thread.  Well, the "type" of objects with head Real
>> in Mathematica is exactly what InexactNumberQ tests for. A
>> mathematica _Real is not a "real number" in the sense of mathematics
>> but precisely an "inexact number".
> Basically I agree with your answer, but what about:
> In[10]:= InexactNumberQ[0.5 I]
> Out[10]= True

Yes, you are completely right. Complex floats are also inexact  
numbers: I simply forgot about them. Actually, I think this is  
another demonstration that Mathematica does not really have anything  
like "types" in other languages (for example, Complex floats have he  
same head as complex integers while real ones have different heads,  
etc. )


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