| Re: Convert hex string to number [message #44564 is a reply to message #44344] |
Fri, 24 June 2005 15:29   |
Michael Wallace
Messages: 409
Registered: December 2003
|
Senior Member |
|
|
Karl Schultz wrote:
> On Fri, 24 Jun 2005 17:02:12 -0500, Michael Wallace wrote:
>
>
>>>> Assume you have a hexadecimal number stored as a string. How do you
>>>> convert this string to a numeric data type? I can easily convert a number
>>>> into a hex string, but how do you go the other way?
>>>>
>>>> -Mike
>>>
>>>
>>>
>>> IDL> s = 'f'
>>>
>>> IDL> reads, s,out,format='(z)'
>>>
>>> IDL> help,out
>>>
>>> OUT FLOAT = 15.0000
>>
>>
>> It seems that when the hex numbers get so big, I start losing precision
>> on the conversion. I have tried a number of different ideas with the
>> format codes, but nothing has worked so far. It appears that reads
>> always stores the output value as a float despite how big the input
>> number is. Is there a way to for it to use double or long on the
>> conversion?
>>
>> IDL> reads, '1234abcd', output, format = '(Z)'
>> IDL> print, output, FORMAT = '(I10)'
>> 305441728
>> IDL> reads, '1234abce', output, format = '(Z)'
>> IDL> print, output, FORMAT = '(I10)'
>> 305441728
>> IDL> reads, '1234abcf', output, format = '(Z)'
>> IDL> print, output, FORMAT = '(I10)'
>> 305441728
>>
>> Something is not right with the above picture...
>>
>> -Mike
>
>
> Docs say:
>
> Note
> If the variable specified for the Vari argument has not been previously
> defined, the input data is assumed to be of type float, and the variable
> will be cast as a float.
>
> So,
>
> output = 1d
>
> before you call READS does the trick.
>
> Karl
Wow. And to think I stared at the reads documentation for so long today
and just missed it. Thanks.
-Mike
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
