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Re: readf help! [message #47511]

Tue, 14 February 2006 11:14

Paul Van Delst[1]
Messages: 1157
Registered: April 2002

Senior Member

Jonathan Wolfe wrote:
> Thank you Paul! That was my problem. I didn't define the variable as
> a long to begin with. Actually, I rarely define them first... A habit I
> will start from now on! Thanks again! Jon

BTW, if you want the code to run even faster, then you may want to read all the data into
a correctly sized array rather than use a for or while loop, e.g. instead of

while not eof(lun) do begin
readf, lun, a, b, c, d, e, f, g, h
.....
endwhile

do something like

pro test_read
openr,lun,'data.asc',/get_lun
nvar=8 ; No of variables in a line
nlin=3 ; No of lines to read
a=dblarr(nvar,nlin) ; Note it's DBL for the "b" time value
readf, lun, a
print, a, format='(8(1x,e16.9))'
free_lun, lun
end

IDL> test_read
1.000000000e+00 1.137369600e+09 0.000000000e+00 0.000000000e+00 2.220000000e+00
-3.000000000e-01 9.300000000e+00 9.400000000e+00
1.000000000e+00 1.137369601e+09 0.000000000e+00 0.000000000e+00 2.220000000e+00
-3.000000000e-01 9.200000000e+00 9.400000000e+00
1.000000000e+00 1.137369602e+09 0.000000000e+00 0.000000000e+00 2.320000000e+00
-3.000000000e-01 9.300000000e+00 9.400000000e+00

The only downside is that you have to know how many lines there are in your data files to
correctly set the "nlin" dimension of "a", but your original post suggested that you do
(the "vs" variable).

paulv

--
Paul van Delst
CIMSS @ NOAA/NCEP/EMC

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[Message index]

		Re: readf help! By: Paul Van Delst[1] on Tue, 14 February 2006 11:14
		Re: readf help! By: vorticitywolfe on Tue, 14 February 2006 09:12
		Re: readf help! By: Paolo Grigis on Tue, 14 February 2006 09:06
		Re: readf help! By: Paul Van Delst[1] on Tue, 14 February 2006 09:04

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