Astropytable

Astropy.table is a subpackage of the Astropy project that provides a flexible, column-oriented data structure and tools for working with tabular data. It centers on the Table object, which can hold heterogeneous columns and metadata, and is designed for use in astronomy but applicable to other scientific domains as well. The package also offers a quantity-aware variant, QTable, for columns with units.

The core data model comprises Table, along with Column and MaskedColumn. A Table stores data in columns that can have different data types (numbers, strings, time, coordinates, etc.). Columns can be created from common Python data structures or NumPy arrays, and Tables support adding, removing, renaming, or reordering columns, as well as row-wise or column-wise slicing. Tables can be built from dictionaries, lists, or other Tables, and sub-tables can be derived through indexing.

Key features include support for units and quantities via QTable, which preserves and propagates astropy.units throughout arithmetic and comparisons. Masked data is handled with MaskedColumn, enabling missing values without breaking computations. Time-related data can be stored in time-aware columns, and the table can interoperate with other Astropy data types.

Astropy.table provides rich I/O capabilities. Tables can be read from and written to formats such as FITS, CSV, ASCII, VOTable, and ECSV, using a unified interface (Table.read and Table.write). It also supports table concatenation and stacking (hstack, vstack) and joining or merging tables to combine datasets.

The package emphasizes interoperability with NumPy and, in some cases, pandas, enabling conversion to and from common data structures. It is widely used for handling astronomical catalogs, survey data, and other tabular datasets that benefit from unit awareness and flexible columnar operations.