| Case for XML (Was: convert very large string to numeric) [message #36256] |
Wed, 27 August 2003 09:43  |
mvukovic
Messages: 63
Registered: July 1998
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Member |
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Paul van Delst <paul.vandelst@noaa.gov> wrote in message news:<3F4B91F6.9F287A27@noaa.gov>...
> Mirko Vukovic wrote:
>>
>> Paul van Delst <paul.vandelst@noaa.gov> wrote in message news:<3F4A7ADE.AF8396AD@noaa.gov>...
>>> Mirko Vukovic wrote:
>>>>
>>>> Hello,
>>>>
>>>> I have a large two column matrix stored as a string,
>>>
>>> Forgive my denseness, but what do you mean exactly when you say you "have a large two
>>> column matrix stored as a string"? By stored do you mean on disk as an ASCII file, or in a
>>> variable as an actual character variable?
>>>
>>> If the latter, my next question is: how did it get that way? (It's not a facetious
>>> question...I'm fishing for more details)
>>>
>>> paulv
>>
>> Hmmm. It seems that my exposition was lacking in crucial details.
>>
>> The data is comming from an E&M simulation program (Maxwell 2D,
>> student version). The really gory details are as follows:
>>
>> - From Maxwell I generate the text file with the data.
>> - With an editor, and insert some XML tags. The file now has a
>> snippet that looks as follows, and whose contents I need to get into
>> IDL
>>
>> <Data-Set>
>> 239843420958.0 23049823048.023984032
>> 3240.83240 0239483.2094
>> 20348.3204 20394803.24
>> .
>> .
>> .
>> 39458.7435 348324.497324
>> </Data-Set>
>>
>> - I use IDL's XML reader (properly customized via inheritance) to read
>> the data.
>
> O.k., so it's the XML read that sticks the data into one big string.
>
> Why not just read the ASCII datafile in one big block and skip the XML read? It'll be a
> lot faster.
>
>> You may wonder why use XML. Well, It strated out as a challenge.
>> But, after I did it for the first time, I was really impressed that I
>> could add some intelligent information to my data files, and my file
>> reader would be able to read them, or skip them, or whatever. So for
>> now, I continue to use them.
>
> How about rather than <Data-Set> you add the number of lines in this data set? (That's
> intelligent information too :o) Then your reader can read the number of lines, allocate
> the required size array and read everything in at once. Using XML may be a little bit
> easier (don't have to count the lines) but you're effectively reading the data twice -
> once from file and once from string->variable.
>
> I doubt this will solve your problem because it seems too simple (my solution, I mean. Not
> your problem.)
>
> paulv
You are absolutely correct. I could do it that way. I used to do it
that way, but decided that it was time to try and learn something new.
In this case XML. And the end result of this learning experience
_may_ be that it is not terribly usefull for what I need right now.
The way I see it right now, the XML data file becomes a bit of a data
base. It contains not just data, but comments, experimental
parameters, info on experiment configuration, etc, all of which can be
retrieved at will. Furthermore, it is _extendable_. I can add
additional information to the file, and not worry that my reader will
not be able to parse it. So in the end, the main advantage is
_EXTENDABILITY_. I guess that where the X comes from :-)
So far I am rather pleased with it's (xml) performance. I just need
to speed it up a bit, or upgrade from my 0.5GHz machine.
Mirko
PS. I looked at the routine that (I forget first name, Reiner?) Bauer
suggested. I think I can easily adapt it to replace the use of
PARSELINE. Thanks.
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| Re: CASE [message #42431 is a reply to message #36256] |
Fri, 04 February 2005 08:26  |
eddie haskell
Messages: 29
Registered: September 1998
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Junior Member |
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>> I want to write this with CASE:
>>
>> CASE str OF
>> 'a': print,'joy!'
>> 'b' OR 'c': print,'ouch!'
>> ELSE: print, '??'
>> ENDCASE
>>
>> obviously this syntax doesn't works
Unless you have your heart really set on using the CASE you could use a
SWITCH instead of a CASE.
Example:
SWITCH str OF
'a' : BEGIN
print,'joy!'
BREAK
END
'b' :
'c' : BEGIN
print, 'ouch!'
BREAK
END
ELSE : print, '??'
ENDSWITCH
Cheers,
eddie
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| Re: CASE [message #42436 is a reply to message #36256] |
Fri, 04 February 2005 03:39 |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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David Lopez Pons writes:
> I want to write this with CASE:
>
> CASE str OF
> 'a': print,'joy!'
> 'b' OR 'c': print,'ouch!'
> ELSE: print, '??'
> ENDCASE
>
> obviously this syntax doesn't works
I would try something like this:
CASE 1 OF
(str EQ 'a'): Print, 'joy'
(str EQ 'b') OR (str EQ 'c'): Print, 'ouch!'
ELSE: Print, '??'
ENDCASE
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
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