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Re: Is there ToNumber?

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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

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  Re: How show axes labels with AxesOrigin->{0,0,0} in 3D? Peter Breitfeld <phbrf@t-online.de> - 2011-06-09 09:45 +0000
  Is there ToNumber? Ted Sariyski <tsariysk@craft-tech.com> - 2011-06-11 07:59 +0000
    Re: Is there ToNumber? Albert Retey <awnl@gmx-topmail.de> - 2011-06-14 11:52 +0000
    How to extract a pattern Ted Sariyski <tsariysk@craft-tech.com> - 2011-06-15 11:20 +0000
    Re: Is there ToNumber? "Hans Michel" <hmichel@cox.net> - 2011-06-16 08:02 +0000
  Re: Is there ToNumber? "Dr. Peter Klamser" <klamser@googlemail.com> - 2011-06-11 10:52 +0000
  Re: Is there ToNumber? "Harvey P. Dale" <hpd1@nyu.edu> - 2011-06-12 09:07 +0000
  Re: Is there ToNumber? ADL <alberto.dilullo@tiscali.it> - 2011-06-12 09:07 +0000
  Re: Is there ToNumber? "Hans Michel" <hmichel@cox.net> - 2011-06-12 23:00 +0000
  Re: Is there ToNumber? "Dr. Peter Klamser" <klamser@googlemail.com> - 2011-06-12 23:01 +0000
  Re: Is there ToNumber? DrMajorBob <btreat1@austin.rr.com> - 2011-06-15 11:19 +0000
  Re: Is there ToNumber? Daniel Lichtblau <danl@wolfram.com> - 2011-06-15 11:19 +0000

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