I would like a simple (one-line) way to a field of a catalog to a given value. This should work for discontiguous catalogs and flag fields (unlike the numpy interface). It should preferably work field names (not just "keys"), since the overhead for lookup occurs only once for setting all fields.
One use case is
RFC-154, where we want to set an "is star" flag field to True for all instances of a subset of a source catalog.