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Re: Is there ToNumber?


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
>



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