| Re: Format codes for comma separated data [message #57750] |
Thu, 20 December 2007 13:32 |
TFE
Messages: 11
Registered: November 2001
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Junior Member |
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Brian Larsen wrote:
> Here is a simple example of the issue:
>
> I made a test file called test_dat.txt that has a bunch of lines of
> a, b, 0, 1, 2, 3
> a, b, 0, 1, 2, 3
> a, b, 0, 1, 2, 3
> a, b, 0, 1, 2, 3
> a, b, 0, 1, 2, 3
> a, b, 0, 1, 2, 3
> a, b, 0, 1, 2, 3
>
>
> IDL> file = 'test_dat.txt'
> IDL> openr, lun, file, /get_lun
> IDL> a = strarr(6)
> IDL> readf, lun, a
> IDL> print, a
> a, b, 0, 1, 2, 3 a, b, 0, 1, 2, 3 a, b, 0, 1, 2, 3 a, b, 0, 1, 2, 3 a,
> b, 0, 1, 2, 3 a, b, 0, 1, 2, 3
>
>
> What I would hope to get would be:
> a, b, 0, 1, 2, 3
>
Brian,
this looks correct-
print, a[0] ;for the first line
Tom
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| Re: Format codes for comma separated data [message #57753 is a reply to message #57750] |
Thu, 20 December 2007 13:08  |
Brian Larsen
Messages: 270
Registered: June 2006
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Senior Member |
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OK, I got it but I'm not sure it makes sense.
for the simple example above the format code:
IDL> readf, lun, dat, format='(2(A,x), 4(I,x))'
% End of input record encountered on file unit: 101.
% Execution halted at: $MAIN$
does not work, while the code:
IDL> readf, lun, dat, format='(2(A2,x), 4(I,x))'
does work
IDL> help, dat, /str
** Structure <1eaa8c4>, 6 tags, length=32, data length=32, refs=1:
A STRING 'a,'
B STRING 'b,'
C INT 0
D INT 1
E INT 2
F INT 3
So if you don't specify the length of the first string it takes
everything?!?!
Brian
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Brian Larsen
Boston University
Center for Space Physics
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| Re: Format codes for comma separated data [message #57754 is a reply to message #57753] |
Thu, 20 December 2007 12:35 |
Brian Larsen
Messages: 270
Registered: June 2006
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Senior Member |
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> I usually use an "x" to represent commas. ;-)
>
> Unless, of course, you want to read them as something.
> But I usually just ignore them.
OK, but none of my format attempts are working... for my simple
example above it seems that format='(2A0,4I0)' should work, but it
doesn't.
IDL> dat = {a:'', b:'', c:0, d:0, e:0, f:0}
IDL> openr, lun, file, /get_lun
IDL> readf, lun, dat, format='(2A0,4I0)'
% End of input record encountered on file unit: 101.
% Execution halted at: $MAIN$
Brian
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Brian Larsen
Boston University
Center for Space Physics
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| Re: Format codes for comma separated data [message #57755 is a reply to message #57754] |
Thu, 20 December 2007 12:30 |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Brian Larsen writes:
> Exactly, how do you include commas in the format statement? They seem
> to just be separators, or I am really slow today... I hope its not
> really slow, or maybe that ok as xmas is close :)
I usually use an "x" to represent commas. ;-)
Unless, of course, you want to read them as something.
But I usually just ignore them.
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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| Re: Format codes for comma separated data [message #57756 is a reply to message #57755] |
Thu, 20 December 2007 12:25 |
Brian Larsen
Messages: 270
Registered: June 2006
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Senior Member |
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> Well, why not use a FORMAT statement, then?
Exactly, how do you include commas in the format statement? They seem
to just be separators, or I am really slow today... I hope its not
really slow, or maybe that ok as xmas is close :)
Brian
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Brian Larsen
Boston University
Center for Space Physics
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| Re: Format codes for comma separated data [message #57757 is a reply to message #57756] |
Thu, 20 December 2007 12:22 |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Brian Larsen writes:
> No the fields are the same line to line, readf is not breaking up the
> line.
>
> When you do
> IDL> dat = strarr(134,3)
> IDL> readf, lun, in, dat
> you dont get one number per array element, you get one line per
> element.
Well, why not use a FORMAT statement, then?
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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| Re: Format codes for comma separated data [message #57759 is a reply to message #57757] |
Thu, 20 December 2007 12:21 |
Brian Larsen
Messages: 270
Registered: June 2006
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Senior Member |
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Here is a simple example of the issue:
I made a test file called test_dat.txt that has a bunch of lines of
a, b, 0, 1, 2, 3
a, b, 0, 1, 2, 3
a, b, 0, 1, 2, 3
a, b, 0, 1, 2, 3
a, b, 0, 1, 2, 3
a, b, 0, 1, 2, 3
a, b, 0, 1, 2, 3
IDL> file = 'test_dat.txt'
IDL> openr, lun, file, /get_lun
IDL> a = strarr(6)
IDL> readf, lun, a
IDL> print, a
a, b, 0, 1, 2, 3 a, b, 0, 1, 2, 3 a, b, 0, 1, 2, 3 a, b, 0, 1, 2, 3 a,
b, 0, 1, 2, 3 a, b, 0, 1, 2, 3
What I would hope to get would be:
a, b, 0, 1, 2, 3
Issue make sense?
Brian
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Brian Larsen
Boston University
Center for Space Physics
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| Re: Format codes for comma separated data [message #57761 is a reply to message #57759] |
Thu, 20 December 2007 12:17 |
Brian Larsen
Messages: 270
Registered: June 2006
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Senior Member |
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On Dec 20, 3:13 pm, David Fanning <n...@dfanning.com> wrote:
> Brian Larsen writes:
>> What I normally do is create a struct array and read a file into that
>> with each column having a structure tag so I can stay organized. But
>> I can't figure out the format codes to do that this time...
>
> Why not? Because they vary from line to line?
>
No the fields are the same line to line, readf is not breaking up the
line.
When you do
IDL> dat = strarr(134,3)
IDL> readf, lun, in, dat
you dont get one number per array element, you get one line per
element.
Brian
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Brian Larsen
Boston University
Center for Space Physics
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| Re: Format codes for comma separated data [message #57764 is a reply to message #57761] |
Thu, 20 December 2007 12:13 |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Brian Larsen writes:
> What I normally do is create a struct array and read a file into that
> with each column having a structure tag so I can stay organized. But
> I can't figure out the format codes to do that this time...
Why not? Because they vary from line to line?
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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