[ANN] argparse 0.3 - Command-line parsing library

Steven Bethard steven.bethard at gmail.com
Tue Dec 5 18:36:30 CET 2006

Announcing argparse 0.3

argparse home:

argparse single module download:

argparse bundled downloads at PyPI:

About this release

This release moves argparse's development status from Pre-Alpha to
Alpha. The API is basically stable, though reasonable change requests
will still be considered.

New in this release

* The '--' pseudo-argument can now be used to terminate the arg list
of an optional::

    >>> parser = argparse.ArgumentParser()
    >>> parser.add_argument('-x', nargs='+')
    >>> parser.add_argument('y')
    >>> parser.parse_args('-x X1 X2 X3 -- Y'.split())
    Namespace(x=['X1', 'X2', 'X3'], y='Y')

About argparse

The argparse module is an optparse-inspired command line parser that
improves on optparse by:

* handling both optional and positional arguments
* supporting parsers that dispatch to sub-parsers
* producing more informative usage messages
* supporting actions that consume any number of command-line args
* allowing types and actions to be specified with simple callables
instead of hacking class attributes like STORE_ACTIONS or

as well as including a number of other more minor improvements on the
optparse API. To whet your appetite, here's a simple program that sums
its command-line arguments and writes them to a file::

    parser = argparse.ArgumentParser()
    parser.add_argument('integers', type=int, nargs='+')
    parser.add_argument('--log', type='outfile', default=sys.stdout)
    args = parser.parse_args()
    args.log.write('%s\n' % sum(args.integers))

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