astropy.table.represent_mixins_as_columns(tbl, exclude_classes=())[source]

Represent input Table tbl using only Column or MaskedColumn objects.

This function represents any mixin columns like Time in tbl to one or more plain ~astropy.table.Column objects and returns a new Table. A single mixin column may be split into multiple column components as needed for fully representing the column. This includes the possibility of recursive splitting, as shown in the example below. The new column names are formed as <column_name>.<component>, e.g. sc.ra for a SkyCoord column named sc.

In addition to splitting columns, this function updates the table meta dictionary to include a dict named __serialized_columns__ which provides additional information needed to construct the original mixin columns from the split columns.

This function is used by astropy I/O when writing tables to ECSV, FITS, HDF5 formats.

Note that if the table does not include any mixin columns then the original table is returned with no update to meta.

tblTable or subclass

Table to represent mixins as Columns

exclude_classestuple of classes

Exclude any mixin columns which are instannces of any classes in the tuple


New Table with updated columns, or else the original input tbl


>>> from astropy.table import Table, represent_mixins_as_columns
>>> from astropy.time import Time
>>> from astropy.coordinates import SkyCoord
>>> x = [100.0, 200.0]
>>> obstime = Time([1999.0, 2000.0], format='jyear')
>>> sc = SkyCoord([1, 2], [3, 4], unit='deg', obstime=obstime)
>>> tbl = Table([sc, x], names=['sc', 'x'])
>>> represent_mixins_as_columns(tbl)
<Table length=2>
 sc.ra   sc.dec sc.obstime.jd1 sc.obstime.jd2    x
  deg     deg
float64 float64    float64        float64     float64
------- ------- -------------- -------------- -------
    1.0     3.0      2451180.0          -0.25   100.0
    2.0     4.0      2451545.0            0.0   200.0