| Re: Splitting An Array Of Strings Without Using Loops [message #35853] |
Thu, 31 July 2003 08:39  |
darrick.white
Messages: 7
Registered: January 2003
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Junior Member |
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JD Smith <jdsmith@as.arizona.edu> wrote in message news:<pan.2003.07.28.23.00.27.659018.15959@as.arizona.edu>...
> On Mon, 28 Jul 2003 11:24:50 -0700, Rick Towler wrote:
>
>
>> "Darrick White" wrote...
>>
>>> It looks like I'm not explaining my problem clearly.
>
>>> Is there a way (not knowing what data set input is used) to transform
>>> my data into the corresponding result array?
>>
>> I don't think the issue is one of clarity, but of possibility. Unless
>> JD can save you with some magical incarnation of HISTOGRAM you are going
>> to have to change your design criteria or use a loop. If performance is
>> really that important write this function in C.
>>
>> -Rick
>
>
> Come on people. I don't use HISTOGRAM for everything. I use it very
> rarely, in fact.
>
> How about something like:
>
> nums=strsplit(strjoin(data,':'),':',/EXTRACT)
> cnts=long(total(byte(data) eq 58b,1))+1L
>
> Now you have a list of tuple-counts and the tuples themselves in a long
> list. You could (yes) use HISTOGRAM or perhaps many other methods to
> stick these into an array as you describe without looping, but rather than
> show something you'd forget 5 minutes after dropping it into your code,
> I'll join Rick in saying that if parsing these strings quickly is this
> important to you, you'll get better results by re-designing the input
> format, or pre-parsing them using a language better suited to these
> manipulations. And on the off chance that you're suffering from the
> "must-optimize-everything-in-sight" disease, you'll want to make sure a
> readable and straightforward input loop won't meet your needs before
> venturing too far into IDL esoterica:
>
> b=make_array(/LONG,VALUE=-1,max(cnt),n_elements(data))
> for i=0,n_elements(data)-1 do b[0,i]=strsplit(data[i],':',/EXTRACT)
>
> Note that there's no integer (long or otherwise) definition of NaN, so I
> used -1.
>
> JD
Thank you.
cnts=long(total(byte(data) eq 58b,1))+1L was what I was looking for.
-Darrick
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