How do I save the header and units of an astropy Table into an ascii file

Question

I'm trying to create an ascii table with some information on the header, the names and units of the columns and some data, it should look like this:

 # ... Header Info ...
          Name | Morphology |         ra_u |        dec_u | ...
               | InNS+B+MOI | HH:MM:SS.SSS | ±DD:MM:SS:SSS| ...
 ==============| ========== | ============ | ============ | ...
 1_Cam_A       | I          | 04:32:01.845 | +53:54:39.03   ...
 10_Lac        | I          | 22:39:15.679 | +39:03:01.01   ... 
...

So far I've tried with numpy.savetxt and astropy.ascii.writhe, numpy won't really solve my problems and with ascii.write I've been able to get something similar but not quite right:

              Name | Morphology |         ra_u |        dec_u | ...    
================== | ========== | ============ | ============ | ...
1_Cam_A            | I          | 04:32:01.845 | +53:54:39.03   ...
...

I'm using this code:

formato= {'Name':'%-23s','Morphology':'%-10s','ra_u':'%s','dec_u':'%s',...}
names=['Name','Morphology','ra_u','dec_u','Mag6']
units=['','InNS+B+MOI','HH:MM:SS.SSS','±DD:MM:SS:SSS',...]
ascii.write(data, output='pb.txt',format='fixed_width_two_line',position_char='=',delimiter=' | ',names=names, formats=formato)

So if I make a print in my terminal the table looks as it should except for the header info, but as I save it into a file the units disappear...

Is there any way to include them in the file?, or I need to save the file and edit it later?

PD: I'm also tried some other formats such as IPAC for ascii.write, in that case the problem is that includes a 4th row in the header like: '| null | null |.....' and I don't know how to get rid of it...

Thanks for the help

Un saludo.

Answer 1

There doesn't appear to be a straightforward way to write out the units of a column in a generic way using astropy.table or astropy.io.ascii . You may want to raise an issue at https://github.com/astropy/astropy/issues with a feature request.

However, there is a pretty simple workaround using the format ascii.ipac :

tbl.write('test.txt', format='ascii.ipac')
with open('test.txt', 'r') as fh:
    output = []
    for ii, line in enumerate(fh):
        if ii not in (1,3):
            output.append(line)

with open('test.txt', 'w') as fh:
    fh.writelines(output)

which will write out in the IPAC format, then remove the 2nd and 4th lines.

Answer 2

除非你的表绝对必须是该格式，如果你想与更多复杂的元数据的ASCII表列，请考虑使用ECSV格式。