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Re: reading an ascii file efficiently [message #68905 is a reply to message #68904]

Fri, 27 November 2009 19:16

Heinz Stege
Messages: 189
Registered: January 2003

Senior Member

On Fri, 27 Nov 2009 11:02:45 -0800 (PST), nata wrote:

> Hi all,
>
> Thanks for your suggestions. Finally, the fastest read time for this
> situation is the following one:
>
> lines=FILE_LINES(file)
> rr=STRARR(lines)
> OPENR, lun, file, /GET_LUN
> READF, lun, rr
> FREE_LUN, lun
>
> result=FLTARR(lines)
> FOR i=0l, lines-1 DO BEGIN
> str_arr=STRSPLIT(rr[i],',',/EXTRACT)
> result[i]=FLOAT(str_arr[6])
> ENDFOR
>
> It's just 0.4 seconds faster than the previous solution. Thanks,
> anyway
>
> nata

What do you think about replacing the for-loop (and the initial array
definition). I would expect the following method to be significantly
faster:

pos=strpos(rr,',',/reverse_search)
result=float(strmid(rr,transpose(pos)))

Have fun, Heinz

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[Message index]

		Re: reading an ascii file efficiently By: jeanh on Mon, 30 November 2009 06:50
		Re: reading an ascii file efficiently By: natha on Mon, 30 November 2009 06:39
		Re: reading an ascii file efficiently By: David Fanning on Sat, 28 November 2009 11:00
		Re: reading an ascii file efficiently By: penteado on Fri, 27 November 2009 21:04
		Re: reading an ascii file efficiently By: David Fanning on Fri, 27 November 2009 20:56
		Re: reading an ascii file efficiently By: penteado on Fri, 27 November 2009 19:58
		Re: reading an ascii file efficiently By: Heinz Stege on Fri, 27 November 2009 19:27
		Re: reading an ascii file efficiently By: Heinz Stege on Fri, 27 November 2009 19:16
		Re: reading an ascii file efficiently By: penteado on Fri, 27 November 2009 14:45
		Re: reading an ascii file efficiently By: natha on Fri, 27 November 2009 11:02
		Re: reading an ascii file efficiently By: jeanh on Fri, 27 November 2009 10:39
		Re: reading an ascii file efficiently By: b_gom on Fri, 27 November 2009 10:34

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