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MathGroup Archive 1994

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Re: EndOfFile

  • To: mathgroup at yoda.physics.unc.edu
  • Subject: Re: EndOfFile
  • From: belopols at marie.mit.edu (Alexander Belopolsky)
  • Date: Sun, 13 Mar 1994 13:24:02 -0500

	Dear Mr. Love,
The `EndOfFile' is a Mathematica symbol ``returned by Read when it reaches
the end of a file'' and is NOT bound to any value. So far Mathematica
can not evaluate "Any string"!=EndOfFile 

In[69]:= "Any string"!=EndOfFile

Out[69]= Any string != EndOfFile

The `While' loop stops either when test gives `False' or when it is
undetermined and that's why when you are using `... != EndOfFile'
Mathematica exits the `While' immediately. 

On the other hand `... != 10' works because

In[71]:= "Any String"!=10

Out[71]= True

and you can use anything but a string which may appear in your file
instead of `10'. Yet I believe, that a more elegant way to do it is to
use `=!=', which returns `False' whenever equality can not be
established.

	Yours, Alexander Belopolsky.

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