Re: Howto turn off using symbols to tag objects?
- To: mathgroup at smc.vnet.net
- Subject: [mg46601] Re: Howto turn off using symbols to tag objects?
- From: Paul Abbott <paul at physics.uwa.edu.au>
- Date: Wed, 25 Feb 2004 13:06:56 -0500 (EST)
- Organization: The University of Western Australia
- References: <c1h0vu$9t5$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
In article <c1h0vu$9t5$1 at smc.vnet.net>, mvdv at spamcop.net (mvyver)
wrote:
> Hi, Does anyone know how to turn this feature off?
> The section in the documentation "Using symbols to tag objects" is
> silent.
I have no idea why you want to do this ...
> My problem is that when trying to remove alphabet characters from a
> string I'm told that "123k" is a number!!
>
> NumberQ[ToExpression["123k"]]
> True
Really? I don't get this behaviour in Version 5.0:
NumberQ[ToExpression["123k"]]
False
If you look at the output of ToExpression["123k"] you will see that you
get 123 k (since Mathematica expressions cannot start with numbers).
You say that your goal is to remove alphabet characters from a string --
so you probably should use String operations. For example,
ReadList[StringToStream["123k"], {Number, String}]
or
DeleteCases[ToExpression /@ Characters["123k"], _?NumberQ]
Cheers,
Paul
--
Paul Abbott Phone: +61 8 9380 2734
School of Physics, M013 Fax: +61 8 9380 1014
The University of Western Australia (CRICOS Provider No 00126G)
35 Stirling Highway
Crawley WA 6009 mailto:paul at physics.uwa.edu.au
AUSTRALIA http://physics.uwa.edu.au/~paul