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Re: readcol procedure [message #32155 is a reply to message #32020]

Fri, 13 September 2002 08:39

Pavel A. Romashkin
Messages: 531
Registered: November 2000

Senior Member

Reimar Bauer wrote:
>
> if you use the eof method you have to read line by line. As you know idl
> is an array orientated language so reading in an array is much faster.
> It's really fast. If you have only 10 lines it doesn't matter but
> sometimes we got datafiles of nearly 100.000 lines. In this case it is
> very important.

I am sorry to disagree.
I routinely read large (60k-200k rows) ASCII files with unknown number
of lines. I always use large arrays to read into and never ever use EOF
with line by line reading.
All I have to do is to catch I/O error in case my buffer array is too
big as my reading approaches the end of file, then look up what size it
should have actually been, resize the buffer, then read the last portion
of file only. Reading a file with 80k lines using this method takes
about 0.1 s.
Take a look:
http://www.ainaco.com/idl/idl_library/read_ascii_columns.pro
Cheers,
Pavel

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[Message index]

		readcol procedure By: shih I Chun on Tue, 10 September 2002 10:15
		Re: readcol procedure By: Liam E. Gumley on Thu, 12 September 2002 08:43
		Re: readcol procedure By: R.Bauer on Thu, 12 September 2002 11:39
		Re: readcol procedure By: David Fanning on Thu, 12 September 2002 08:59
		Re: readcol procedure By: R.Bauer on Wed, 11 September 2002 23:42
		Re: readcol procedure By: David Fanning on Wed, 11 September 2002 14:12
		Re: readcol procedure By: Wayne Landsman on Wed, 11 September 2002 07:54
		Re: readcol procedure By: R.Bauer on Tue, 10 September 2002 23:33
		Re: readcol procedure By: Don J Lindler on Tue, 10 September 2002 13:30
		Re: readcol procedure By: R.Bauer on Sun, 15 September 2002 08:16
		Re: readcol procedure By: Pavel A. Romashkin on Fri, 13 September 2002 12:30
		Re: readcol procedure By: R.Bauer on Fri, 13 September 2002 10:43
		Re: readcol procedure By: Pavel A. Romashkin on Fri, 13 September 2002 09:36
		Re: readcol procedure By: David Fanning on Fri, 13 September 2002 08:50
		Re: readcol procedure By: Pavel A. Romashkin on Fri, 13 September 2002 08:39
		Re: readcol procedure By: R.Bauer on Thu, 12 September 2002 14:05
		Re: readcol procedure By: Liam E. Gumley on Thu, 12 September 2002 12:11

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