| Re: Read Total lines in an ASCII file [message #33271 is a reply to message #33175] |
Tue, 17 December 2002 13:40   |
wmconnolley
Messages: 106
Registered: November 2000
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Senior Member |
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Mark Hadfield <m.hadfield@niwa.co.nz> wrote:
> Method 1, the two-pass method, is
> surprisingly quick here, but suffers if the file is on a slow network
> drive.
If the read and re-read are close in time (as they should be) the file
will still be in whatever cache the o/s uses, and the second read (as
far as the o/s is concerned) will be much faster. On the ex-dec alphas
I use, faster by a factor of 10 than the first. Whether putting IDL in
between harms this gain I don't know. This may well survive being on a
network drive (I'm assuming what you say above is a guess, rather than
experience? Forgive me if not)
ps: did you try method 5, ie spawn wc -l, then use method 0?
-W.
--
William M Connolley | wmc@bas.ac.uk | http://www.nerc-bas.ac.uk/icd/wmc/
Climate Modeller, British Antarctic Survey | Disclaimer: I speak for myself
I'm a .signature virus! copy me into your .signature file & help me spread!
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