[AstroPy] How can I create a VOtable from a python list?

Jean-Baptiste Marquette marquett@iap...
Wed Mar 6 08:28:44 CST 2013


Hi all,

May I suggest to have a look at ATpy, where VOTable are natively recognized: http://atpy.github.com/ ?

BTW, I would be very grateful if both AstroPy and ATpy could merge…

Cheers,
Jean-Baptiste

Le 6 mars 2013 à 15:08, Michael Droettboom a écrit :

> The general approach you're taking here -- to create a Table and then 
> convert it to a VOTable -- is the right one here.  The Table class has a 
> much richer set of things it can convert to and from (it's sort of our 
> "hub" class for everything that's table like).
> 
> However, I don't believe it supports construction from a list in the way 
> you're trying.  There is a doc page about constructing a table here, 
> that may be helpful:
> 
> https://astropy.readthedocs.org/en/v0.2/table/construct_table.html
> 
> That said, I tried to convert your example to the form where the Table 
> is constructed from a Numpy structured array, and still ran into the 
> same exception:
> 
> from astropy import table
> 
> from astropy.io import votable
> 
> import numpy as np
> 
> x = np.array(
> 
>     [("CIG12",1.2345,0,2,999,"COMMENT"),
> 
>      ("CIG122",1.23452,0,2,9992,"COMMENT2")],
> 
>     dtype=[('a', str), ('b', float), ('c', int), ('d', int), ('e', int), ('f', str)])
> 
> print x.dtype
> 
> t = table.Table(x)
> 
> votable = votable.tree.VOTableFile.from_table(t)
> 
> 
> So maybe we're both still doing something wrong.  I've Cc'd Tom 
> Aldcroft, the primary author of the Table class, as he might have more 
> insight.
> 
> Mike
> 
> 
> On 03/04/2013 06:43 AM, Susana Sanchez wrote:
>> Hello all,
>> 
>> How can I create a VOtable from a list (a python list) of rows using astropy?
>> 
>> Reading the documentation, I found the method "from_table" of the
>> class VOTableFile, this method needs as argument an instance of the
>> class astropy.table.table.Table, so I did the following:
>> 
>> t=astropy.table.table.Table([["CIG12",1.2345,0,2,999,"COMMENT"],["CIG122",1.23452,0,2,9992,"COMMENT2"]])
>> votable = VOTableFile()
>> votable.from_table(t)
>> 
>> 
>> But here I got this error:
>> 
>> /usr/local/lib/python2.6/dist-packages/numpy/ma/core.pyc in
>> __new__(cls, data, mask, dtype, copy, subok, ndmin, fill_value,
>> keep_mask, hard_mask, shrink, **options)
>>    2692             # Or assume it's a sequence of bool/int
>> 
>>    2693             except TypeError:
>> -> 2694                 mask = np.array([tuple([m] * len(mdtype)) for
>> m in mask],
>>    2695                                  dtype=mdtype)
>>    2696             # Make sure the mask and the data have the same shape
>> 
>> TypeError: 'NoneType' object is not iterable
>> 
>> 
>> Reading the error message,  I thought it could be related with the
>> mask, so I tried to create the mask of the table t (with the method
>> t.create_mask()), and then to build the VOTableFile from this table,
>> but I got the same error.
>> 
>> I would be very gratefully, If anyone can help me or give me any hint.
>> 
>> Thanks,
>> Susana.
>> _______________________________________________
>> AstroPy mailing list
>> AstroPy@scipy.org
>> http://mail.scipy.org/mailman/listinfo/astropy
> 
> _______________________________________________
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