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Re: undocumented function: StringQ

  • To: mathgroup at smc.vnet.net
  • Subject: [mg47630] Re: undocumented function: StringQ
  • From: bobhanlon at aol.com (Bob Hanlon)
  • Date: Mon, 19 Apr 2004 04:33:00 -0400 (EDT)
  • References: <c5qjch$g0e$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

If you type a partial name after "?" (say "?Str") the "Complete Selection" key
shortcut or menu item will offer all defined names such as StringQ for easy
access to the usage statement.


Bob Hanlon

<< Subject: [mg47630] Re: undocumented function: StringQ
From: drbob at bigfoot.com  (Bobby R. Treat)
To: mathgroup at smc.vnet.net

>>I just noticed that there is a built-in test StringQ[],
>> that is not documented in the online help

You don't mean "online help", you mean on DISK help. Try searching for
StringQ at Wolfram's online Documentation Center
http://documents.wolfram.com/ and you'll find hundreds of unrelated
articles, in addition to a few that actually mention this function. In
addition, this works:

?StringQ
StringQ[expr] gives True if expr is a string, and False otherwise.

If you look up String in the Help Browser and look at topics under
String Manipulation, StringQ isn't listed, and this is what I call
undocumented: we can't find out about it unless somebody tells us
about it, we see it in a post like this, et cetera. We can't look it
up at the Doc Center or use ? unless we know it exists and we know its
precise name.

By that definition, there are hundreds, probably thousands of
undocumented functions and features. Help for complex topics is poorly
written, too -- apparently by programmers with little or no skill in
writing for an audience.

That said, Mathematica is more complex and better documented than
Visual Basic for Applications, Excel, et cetera, so.... We're lucky.

Bobby

Marcus Stollsteimer <marcus314 at yahoo.com> wrote in message
news:<c5o9i7$16q$1 at smc.vnet.net>...
> Hi,
> 
> I just noticed that there is a built-in test StringQ[],
> that is not documented in the online help.
> 
> ?StringQ
> StringQ[expr] gives True if expr is a string, and False otherwise.
> 
> Only a mistake?
> Is it unsafe to use this function?
> 
> Regards,
> Marcus





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