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question on changing 'type' of numbers


I think of a the Head of expression as its 'type'.

One is supposed to be able to use Apply[f,expr] to change head of expression 
to f.

But Why can't I use this to change the head of a Real number to Integer?

In[122]:=
Remove["Global`*"]
x = 0.1
Head[x]
           -------------->Real
Apply[Integer,x]
Head[x]
        ------------------->Real. I was expecting Intger
x = Integer[x]
Head[x]
      ----------------> Now it says Integer

any idea?

ofcourse the question as to what should happen to the value of the variable 
if for example I change the head of 0.5 from Real to Integer is another 
matter. It seems in this case x remained 0.1 but only the head said Integer

x
----->Integer[0.1]

Now sure what the above really means :)

Nasser 


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