| Re: defining structure after ascii template [message #85884 is a reply to message #85882] |
Mon, 16 September 2013 10:51   |
spluque
Messages: 33
Registered: September 2013
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On Monday, September 16, 2013 12:24:29 PM UTC-5, David Fanning wrote:
> spluque@gmail.com writes:
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>> On Monday, September 16, 2013 11:02:11 AM UTC-5, David Fanning wrote:
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>>> spluque@gmail.com writes:
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>>>> As far as I can see, it is not possible to define a structure using a template as the one built via ascii_template(). Essentially, extract a sub-structure from the template returned by ascii_template, containing the column names as tags and the field type. What is the proper way to do this?
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>>> I honestly have no idea what this question means. Why don't you explain
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>>> to us what you are trying to do.
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>> Sorry for the terse initial post. Here is what I am trying to do:
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>> 1. I've prepared a template with ascii_template() for reading in an ASCII file via read_ascii().
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>> 2. Before reading the data with read_ascii(), I need to prepare an *array* of structures, where each element is a record (row) in a number of files to be read with the template in (1).
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>> 3. read_ascii() creates a structure that looks like this:
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>> help, data, /structures
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>> ** Structure <57e3008>, 23 tags, length=7800864, data length=7800864, refs=1:
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>> FIELD01 LONG Array[84792]
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>> FIELD02 FLOAT Array[84792]
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>> FIELD03 LONG Array[84792]
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>> ...[many more fields]
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>> So the array of structures to be created would like this (abbreviating the number of fields for brevity here):
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>> p={'foo', FIELD01:0L, FIELD02:0.0, FIELD03:0L}
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>> replicate(p, n_recs)
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>> where n_recs is the total number of records expected.
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>> So the question is how can p be created from the information already there in the template created in (1)?
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> Well, p *is* the structure you obtained. I guess I don't see the
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> problem:
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> IDL> struct = ascii_template()
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> IDL> help, struct
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> ** Structure <701c24d0>, 10 tags, length=320, data length=313, refs=1:
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> VERSION FLOAT 1.00000
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> DATASTART LONG 0
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> DELIMITER BYTE 32
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> MISSINGVALUE FLOAT NaN
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> COMMENTSYMBOL STRING ''
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> FIELDCOUNT LONG 10
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> FIELDTYPES LONG Array[10]
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> FIELDNAMES STRING Array[10]
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> FIELDLOCATIONS LONG Array[10]
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> FIELDGROUPS LONG Array[10]
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> IDL> data = Replicate(struct, 100)
Thanks for your patience David. The problem is that the template structure is not quite the same as the one created by read_ascii(); compare the output you got with the one in point (2) of my previous message. In other words, what I need to replicate is an element of the output of read_ascii(), but without having to call it first. Hopefully, this is clearer.
Cheers,
Seb
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