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Re: Lots of files [message #53136 is a reply to message #53040]

Sat, 17 March 2007 20:59

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

Lasse Clausen writes:

> Well thanks, that works, however it did not bring the speed boost I
> had hoped for. So I had another thought: Actually, all data is one
> line, not in one line per station as I said earlier. But I know that
> each data set is 1440 characters long, so here is the outline of my
> code, after I opened all the files:
>
> info = file_info(input_filename)
> lines = info.size/1440L
>
> for i=0L, lines-1L do begin
> point_lun, fin, i*1440L
> readf, fin, line, format='(A1440)'
> ; extracting station name
> hstat = strlowcase(strmid(line, 12, 3))
> ; find correct file unit
> tmp = where(stats eq hstat)
> printf, tmp[0]+1, line
> endfor

Well lots of string processing and WHERE's going
on here, which I think is what is slowing things
down. How about something like this:

theLines = Assoc(lun, BytArr(1440))
maxYear = Max(stats)
for I=0L, lines-1L do begin
aLine = theLines[I]
; extracting station name
hstat = String(aLine[12:15])
; find correct file unit
printf, (maxYear-hstat)+1, String(aLine)
endfor

Cheers,

David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")

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[Message index]

		Re: Lots of files By: lasse on Sat, 17 March 2007 10:32
		Re: Lots of files By: David Fanning on Fri, 16 March 2007 14:23
		Re: Lots of files By: Paul Van Delst[1] on Fri, 16 March 2007 13:07
		Re: Lots of files By: David Fanning on Fri, 16 March 2007 13:53
		Re: Lots of files By: David Fanning on Sat, 17 March 2007 20:59
		Re: Lots of files By: Foldy Lajos on Sat, 17 March 2007 13:42

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