[AstroPy] Convert FITS header into astropy Table entries?

[Jens Melinder]

Hi,
there are a couple of problems with doing it that way I think. 

1. Table will not like column names with the same name. For fits headers these are the HISTORY and COMMENT fields which will have multiple entries in the output list you get from h0.keys().
2. While not 100% certain I think also the empty keys (which are used to split the HST fist headers into different sections) will cause problems.
3. Finally, there is also a small syntax error in your call to Table. Instead of writing rows=h0.values() you should write rows = [h0.values()] (making it a list of lists)

If you don’t need the HISTORY and COMMENT fields a simple fix maybe something like this:
keys_cl=[]
vals_cl=[]
for ii in range(len(h0.keys())):
	if (h0.keys()[ii] != ’’)&(h0.keys()[ii] != ’HISTORY’)&(h0.keys()[ii] != ’COMMENT’):
		keys_cl.append(h0.keys()[ii])
		vals_cl.append(h0.values()[ii])

tab = Table(rows=[vals_cl],names=keys_cl)

Good luck,
Jens 

19 aug 2015 kl. 16:00 skrev Jason Tumlinson <tumlinson at stsci.edu>:

> Hi,
> I am trying to harvest the information from a large number of FITS headers, parse them and do statistics on values, in an efficient manner. I read in each header in the usual fashion: 
> 
> h = fits.open('lbiy83i0q_x1d.fits’)
> h0 = h[0].header
> 
> My goal then is to get all the header info into an astropy Table such that the table columns are given by the header keys and the values in the rows are given by the values in each of 100+ headers. I tried this: 
> 
> In [38]: t = Table(rows=h0.values(), names=h0.keys())
> ---------------------------------------------------------------------------
> TypeError                                 Traceback (most recent call last)
> <ipython-input-38-8a0ece2925d5> in <module>()
> ----> 1 t = Table(rows=h0.values(), names=h0.keys())
> 
> /Users/tumlinson/Ureka/python/lib/python2.7/site-packages/astropy/table/table.pyc in __init__(self, data, masked, names, dtype, meta, copy, rows)
>     240                 data = rows
>     241             else:
> --> 242                 rec_data = recarray_fromrecords(rows)
>     243                 data = [rec_data[name] for name in rec_data.dtype.names]
>     244 
> 
> /Users/tumlinson/Ureka/python/lib/python2.7/site-packages/astropy/table/np_utils.pyc in recarray_fromrecords(rec_list)
>     604     # to column arrays in the recarray module; it could be there is a better
>     605     # way
> --> 606     nfields = len(rec_list[0])
>     607     obj = np.array(rec_list, dtype=object)
>     608     array_list = [np.array(obj[..., i].tolist()) for i in range(nfields)]
> 
> TypeError: object of type 'bool' has no len()
> 
> to no avail. Is this possible, easy, or wrongheaded? Advise appreciated. 
> 
> Thanks, 
> JT
> 
> 
> 
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-----------------------------------
Jens Melinder
Department of Astronomy
Stockholm University
jens at astro.su.se
+46 706471856




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