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Re: Is there ToNumber?

On 06/14/2011 05:13 AM, SigmundV wrote:
> I had imagined that applying Real to the string would make it a
> number, e.g. Real@@"1.2", but it doesn't work:
> In[1]:= Head[Real @@ "1.2"]
> Out[1]= String
> Of course ToExpression works as intented:
> In[2]:= Head[ToExpression@"1.2"]
> Out[2]= Real
> Why can't I simply change the head of a string by using Apply?

Same reason one cannot change the head of an Integer. They are atomic.

In[3]:= Apply[Integer,1.0]

Out[3]= 1.

Moreover, even if String was not atomic an type, there is neither 
documentation nor functionality to suggest Real converts input to real 

Daniel Lichtblau
Wolfram Research

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