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From: Simon on 27 May 2010 06:45
Nice!

I don't think that it's a "bug" but it is a little unexpected.
ToString produces a kind of "pretty print" output, e.g.
ToString[1/3] yields an string that prints as fraction: "1\n-\n3".
This is controlled by the FormatType option. By default it is
OutputForm.

If you want a string that you can turn back into an expression, try
ToExpression[ToString[1/3, InputForm]]

This should probably be included in the "Possible Issues" section of
the documentation....

Simon

On May 26, 7:09 pm, James Stein <mathgr...(a)stein.org> wrote:
> Evaluating:
>
> ToExpression [ ToString [ 1/3 ] ]
>
> I did not expect negative three!
>
> Bug? or a lack in my understanding?


From: Murray Eisenberg on 27 May 2010 06:45
I don't understand the result either, but I have a clue:

FullForm[ToString[1/3]]
"1\n-\n2"

I would actually expect the result to be a pair of output cells, namely:

1

-2

On 5/26/2010 7:10 AM, James Stein wrote:
> Evaluating:
>
> ToExpression [ ToString [ 1/3 ] ]
>
> I did not expect negative three!
>
> Bug? or a lack in my understanding?
>
>

--
Murray Eisenberg murray(a)math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower phone 413 549-1020 (H)
University of Massachusetts 413 545-2859 (W)
710 North Pleasant Street fax 413 545-1801
Amherst, MA 01003-9305

From: Bill Rowe on 27 May 2010 06:46
On 5/26/10 at 7:10 AM, mathgroup(a)stein.org (James Stein) wrote:

>Evaluating:

>ToExpression [ ToString [ 1/3 ] ]

>I did not expect negative three!

>Bug? or a lack in my understanding?

Do ToCharacterCode[ToString[1/3]] and you will find the
character code for 1, - and 3 all followed by line termination
characters. On Unix or Mac OS this is a line feed character and
possibly different on Windows. In any case, this is seen as an
implicit multiply yielding -3.


From: David Bailey on 28 May 2010 07:20
On 27/05/10 11:45, Murray Eisenberg wrote:
> ToExpression [ ToString [ 1/3 ] ]
And indeed,
ToExpression[ToString[1/3,InputForm]]
works as expected!

David Bailey

www.dbaileyconsultancy.co.uk

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