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- Reading and Writing Table Objects

# Reading and Writing Table Objects

`astropy` provides a unified interface for reading and writing data in different formats. For many common cases this will streamline the process of file I/O and reduce the need to learn the separate details of all of the I/O packages within `astropy`. For details and examples of using this interface see the Unified File Read/Write Interface section.

## Getting Started

The `Table` class includes two methods, `read()` and `write()`, that make it possible to read from and write to files. A number of formats are automatically supported (see Built-In Table Readers/Writers) and new file formats and extensions can be registered with the `Table` class (see I/O Registry (astropy.io.registry)).

To use this interface, first import the `Table` class, then call the `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 catalogs 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 `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 Built-In Table Readers/Writers. This section also provides the full list of choices for the `format` argument.

## Supported Formats

The Unified File Read/Write Interface has built-in support for the following data file formats:

- ASCII Formats

- HDF5

- FITS

- VO Tables

- Parquet