|AHELP for CIAO 4.9||
Create a vector column.
create_vector_column(colname, cptnames, source=None)
|colname||The name of the vector column.|
|cptnames||A list of the component names.|
|source||If not None, then the new vector column will be a virtual column for the source column (which should also be a vector column); see also create_virtual_column().|
The create_vector_column command creates a vector column, as well as the component vectors, and returns it as a CrateData object. The values attribute of the returned object can be used to set the row values.
>>> cr = TABLECrate() >>> sky = create_vector_column('sky', ['x', 'y']) >>> sky.unit = 'pixel' >>> sky.desc = 'Simulated Sky coordinate' >>> nrows = 1000 >>> x = np.random.normal(4723.42, 2, size=nrows) >>> y = np.random.normal(3888.21, 2, size=nrows) >>> sky.values = np.column_stack((x, y)) >>> cr.add_column(sky) >>> cr.write('tbl.fits') >>> cr.write('tbl.dat[opt kernel=text/simple]')
This example shows how to create a 200-row file with a single vector called "sky". The components of "sky" are "x" and "y" and contain random numbers normally distributed around 4723.42 and 3888.21 respectively, both with a standard deviation of 2. The file is written out both as a FITS table (tbl.fits) and an ascii file (tbl.dat).
See the bug pages on the CIAO website for an up-to-date listing of known bugs.
Refer to the CIAO bug pages for an up-to-date listing of known issues.