Services & ResourcesWolfram ForumsMathGroup Archive

[Date Index] [Thread Index] [Author Index]

Re: Is there ToNumber?

• To: mathgroup at smc.vnet.net
• Subject: [mg119626] Re: Is there ToNumber?
• From: Ted Sariyski <tsariysk at craft-tech.com>
• Date: Wed, 15 Jun 2011 07:19:19 -0400 (EDT)
• References: <isnllk$n7b$1@smc.vnet.net> <201106090945.FAA06238@smc.vnet.net> <isv78n$80$1@smc.vnet.net> <201106141151.HAA07409@smc.vnet.net>

Hi,
>  would be necessary to specify where these strings come from...

I had to extract the time stamp from the file names.

>Is there a reason why you
>think that is not good enough?

That is exactly what I am doing and it works fine. The only reason I 
posted the question was because I felt that I am missing  something.

Thanks,
--Ted

  On 6/14/2011 7:51 AM, Albert Retey wrote:
> Hi,
>
> the short answer is: no.
>
>> Is there a built-in function which returns the numeric value of a string
>> (like ToString but inverse).  Currently I use mine function toNumber:
>>
>>     ch = StringToStream[timeStr];
>>     timeNum = Read[ch, Number];
>>     Close[ch];
>>
>> but I suspect there is easier way.
> The question is what kind of input you expect "ToNumber" to handle. As
> others have pointed out ToExpression is the most simple and also
> relatively fast but only works for numbers given in Mathematica syntax.
> If you need to handle other formats, then there are alternatives to what
> you do, but they seem to be slower if used in a naive way, e.g.:
>
> ImportString["1e3", "Table"][[1, 1]]
>
> whether you consider that to be "easier" is another question. What about
> defining:
>
> toNumber[s_String] := Module[{ch, res},
>     ch = StringToStream[s];
>     res = Read[ch, Number];
>     Close[ch];
>     res
>     ];
>
> This is easy to use and also relatively fast. Is there a reason why you
> think that is not good enough? If you need further advice, I think it
> would be necessary to specify where these strings come from...
>
> hth,
>
> albert
>

• Follow-Ups:
  • Re: Is there ToNumber?
    • From: "Hans Michel" <hmichel@cox.net>

• References:
  • Re: How show axes labels with AxesOrigin->{0,0,0} in 3D?
    • From: Peter Breitfeld <phbrf@t-online.de>
  • Re: Is there ToNumber?
    • From: Albert Retey <awnl@gmx-topmail.de>