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Re: Sneaky white space

  • To: mathgroup at smc.vnet.net
  • Subject: [mg113423] Re: Sneaky white space
  • From: David Bailey <dave at removedbailey.co.uk>
  • Date: Thu, 28 Oct 2010 04:26:17 -0400 (EDT)
  • References: <ia8qin$1m3$1@smc.vnet.net>

On 27/10/10 10:15, John Fultz wrote:
> On Tue, 26 Oct 2010 08:56:32 -0700 (PDT), Sam Takoy wrote:
>> From: John Fultz<jfultz at wolfram.com>
>> To: sam.takoy at yahoo.com; mathgroup at smc.vnet.net
>> Sent: Tue, October 26, 2010 10:49:12 AM
>> Subject: Re:  Sneaky white space
>> On Tue, 26 Oct 2010 05:35:41 -0400 (EDT), Sam Takoy wrote:
>>> Hi,
>>>
>>> I'm working nicely along, when all of a sudden Mathematica tells me that
>>> essentially it can't NIntegrate[Cos[a], {a, -Pi, Pi}]. After 30 minutes
>>> of searching, I discover that I have an invisible TextCell[""] attached
>>> to the expression.
>>>
>>> First of all, I don't know what I did to put it there. What DID I do?
>>> Some inadvertent Ctrl-Key combination?
>>>
>>> Second, TextCell[""] is mostly invisible and hard to find. Is there a
>>> way to make it visible or to find it more easily?
>>>
>>> Many thanks in advance,
>>>
>>>
>>> Sam
>>>
>> It's hard to offer any definitive comments without knowing more about wha=
> t
>> happened, but I'll offer a bit of speculation.
>>
>> Possibly you may have accidentally pressed Ctrl+9 at some point while
>> editing
>> the input?  Or maybe this got snagged as part of
>> some copy/paste operation.  Did
>> you maybe copy the template from the help viewer?  Or copy output from
>> some
>> other input you had involving TextCell?
>>
>> A TextCell which is truly empty ought to disappear on its own unless it
>> was
>> created by evaluating TextCell[].  It also wouldn't go away if it had
>> spaces in
>> it.
>>
>> Sincerely,
>>
>> John Fultz
>> jfultz at wolfram.com
>> User Interface Group
>> Wolfram Research, Inc.
>>
>>
>> Thank you. I may have done one of those things, but didn't TextCell
>> anywhere. Perhaps, Print[] is related?
>>
>>
>> And also, I guess my question is - is it possible to make a TextCell
>> visible? Like set it's background to red or border to another color?
>>
>>
>> Thanks again,
>>
>>
>> Sam
>
> I can't think of an easy way off the top of my head.  Sorry.
>
> Sincerely,
>
> John Fultz
> jfultz at wolfram.com
> User Interface Group
> Wolfram Research, Inc.
>

I think the lesson to learn from that - which I find useful from time to 
time - is that if a piece of input seems to generate spurious syntax 
errors, or responds in some very peculiar way, it is worth trying 
re-typing it, possibly by cutting and pasting the text in question to a 
text editor and back again!

David Bailey
http://dbaileyconsultancy.co.uk




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