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.. doctest-skip-all
.. _read_write_tables:
Reading and writing Table objects
===================================
Astropy provides a unified interface for reading and writing data
in different formats. For many common cases this will
simplify the process of file I/O and reduce the need to master
the separate details of all the I/O packages within Astropy. For details and
examples of using this interface see the :ref:`table_io`
section.
Getting started
----------------
The :class:`~astropy.table.Table` class includes two methods,
:meth:`~astropy.table.Table.read` and
:meth:`~astropy.table.Table.write`, that make it possible to read from
and write to files. A number of formats are automatically supported (see
:ref:`built_in_readers_writers`) and new file formats and extensions can be
registered with the :class:`~astropy.table.Table` class (see
:ref:`io_registry`).
To use this interface, first import the :class:`~astropy.table.Table` class, then
simply call the :class:`~astropy.table.Table`
:meth:`~astropy.table.Table.read` method with the name of the file and
the file format, for instance ``'ascii.daophot'``::
>>> from astropy.table import Table
>>> t = Table.read('photometry.dat', format='ascii.daophot')
It is possible to load tables directly from the Internet using URLs. For example,
download tables from Vizier catalogues in CDS format (``'ascii.cds'``)::
>>> t = Table.read("ftp://cdsarc.u-strasbg.fr/pub/cats/VII/253/snrs.dat",
... readme="ftp://cdsarc.u-strasbg.fr/pub/cats/VII/253/ReadMe",
... format="ascii.cds")
For certain file formats, the format can be automatically detected, for
example from the filename extension::
>>> t = Table.read('table.tex')
Similarly, for writing, the format can be explicitly specified::
>>> t.write(filename, format='latex')
As for the :meth:`~astropy.table.Table.read` method, the format may
be automatically identified in some cases.
Any additional arguments specified will depend on the format. For examples of this see the
section :ref:`built_in_readers_writers`. This section also provides the full list of
choices for the ``format`` argument.
Supported formats
------------------
The :ref:`table_io` has built-in support for the following data file formats:
* :ref:`table_io_ascii`
* :ref:`table_io_hdf5`
* :ref:`table_io_fits`
* :ref:`table_io_votable`
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