.. code-block:: text
- usage: <yourscript> [options]
+ Usage: <yourscript> [options]
- options:
+ Options:
-h, --help show this help message and exit
-f FILE, --file=FILE write report to FILE
-q, --quiet don't print status messages to stdout
.. code-block:: text
- usage: <yourscript> [options] arg1 arg2
+ Usage: <yourscript> [options] arg1 arg2
- options:
+ Options:
-h, --help show this help message and exit
-v, --verbose make lots of noise [default]
-q, --quiet be vewwy quiet (I'm hunting wabbits)
is then printed before the detailed option help.
If you don't supply a usage string, :mod:`optparse` uses a bland but sensible
- default: ``"usage: %prog [options]"``, which is fine if your script doesn't
+ default: ``"Usage: %prog [options]"``, which is fine if your script doesn't
take any positional arguments.
* every option defines a help string, and doesn't worry about line-wrapping---
default value. If an option has no default value (or the default value is
``None``), ``%default`` expands to ``none``.
+Grouping Options
+++++++++++++++++
+
When dealing with many options, it is convenient to group these options for
better help output. An :class:`OptionParser` can contain several option groups,
each of which can contain several options.
-Continuing with the parser defined above, adding an :class:`OptionGroup` to a
-parser is easy::
+An option group is obtained using the class :class:`OptionGroup`:
+
+.. class:: OptionGroup(parser, title, description=None)
+
+ where
+
+ * parser is the :class:`OptionParser` instance the group will be insterted in
+ to
+ * title is the group title
+ * description, optional, is a long description of the group
+
+:class:`OptionGroup` inherits from :class:`OptionContainer` (like
+:class:`OptionParser`) and so the :meth:`add_option` method can be used to add
+an option to the group.
+
+Once all the options are declared, using the :class:`OptionParser` method
+:meth:`add_option_group` the group is added to the previously defined parser.
+
+Continuing with the parser defined in the previous section, adding an
+:class:`OptionGroup` to a parser is easy::
group = OptionGroup(parser, "Dangerous Options",
"Caution: use these options at your own risk. "
.. code-block:: text
- usage: [options] arg1 arg2
+ Usage: <yourscript> [options] arg1 arg2
+
+ Options:
+ -h, --help show this help message and exit
+ -v, --verbose make lots of noise [default]
+ -q, --quiet be vewwy quiet (I'm hunting wabbits)
+ -f FILE, --filename=FILE
+ write output to FILE
+ -m MODE, --mode=MODE interaction mode: novice, intermediate, or
+ expert [default: intermediate]
+
+ Dangerous Options:
+ Caution: use these options at your own risk. It is believed that some
+ of them bite.
+
+ -g Group option.
+
+A bit more complete example might invole using more than one group: still
+extendind the previous example::
+
+ group = OptionGroup(parser, "Dangerous Options",
+ "Caution: use these options at your own risk. "
+ "It is believed that some of them bite.")
+ group.add_option("-g", action="store_true", help="Group option.")
+ parser.add_option_group(group)
+
+ group = OptionGroup(parser, "Debug Options")
+ group.add_option("-d", "--debug", action="store_true",
+ help="Print debug information")
+ group.add_option("-s", "--sql", action="store_true",
+ help="Print all SQL statements executed")
+ group.add_option("-e", action="store_true", help="Print every action done")
+ parser.add_option_group(group)
+
+that results in the following output:
+
+.. code-block:: text
+
+ Usage: <yourscript> [options] arg1 arg2
+
+ Options:
+ -h, --help show this help message and exit
+ -v, --verbose make lots of noise [default]
+ -q, --quiet be vewwy quiet (I'm hunting wabbits)
+ -f FILE, --filename=FILE
+ write output to FILE
+ -m MODE, --mode=MODE interaction mode: novice, intermediate, or expert
+ [default: intermediate]
+
+ Dangerous Options:
+ Caution: use these options at your own risk. It is believed that some
+ of them bite.
+
+ -g Group option.
+
+ Debug Options:
+ -d, --debug Print debug information
+ -s, --sql Print all SQL statements executed
+ -e Print every action done
+
+Another interesting method, in particular when working programmatically with
+option groups is:
- options:
- -h, --help show this help message and exit
- -v, --verbose make lots of noise [default]
- -q, --quiet be vewwy quiet (I'm hunting wabbits)
- -fFILE, --file=FILE write output to FILE
- -mMODE, --mode=MODE interaction mode: one of 'novice', 'intermediate'
- [default], 'expert'
+.. method:: OptionParser.get_option_group(opt_str)
- Dangerous Options:
- Caution: use of these options is at your own risk. It is believed that
- some of them bite.
- -g Group option.
+ Return, if defined, the :class:`OptionGroup` that has the title or the long
+ description equals to *opt_str*
.. _optparse-printing-version-string:
that takes an integer::
$ /usr/bin/foo -n 4x
- usage: foo [options]
+ Usage: foo [options]
foo: error: option -n: invalid integer value: '4x'
Or, where the user fails to pass a value at all::
$ /usr/bin/foo -n
- usage: foo [options]
+ Usage: foo [options]
foo: error: -n option requires an argument
.. code-block:: text
- usage: foo.py [options]
+ Usage: foo.py [options]
- options:
+ Options:
-h, --help Show this help message and exit
-v Be moderately verbose
--file=FILENAME Input file to read data from
option strings. Now ``--dry-run`` is the only way for the user to activate
that option. If the user asks for help, the help message will reflect that::
- options:
+ Options:
--dry-run do no harm
[...]
-n, --noisy be noisy
At this point, the original ``-n``/``--dry-run`` option is no longer
accessible, so :mod:`optparse` removes it, leaving this help text::
- options:
+ Options:
[...]
-n, --noisy be noisy
--dry-run new dry-run option
The :class:`Formatter` class has the following public methods:
- .. method:: format(format_string, *args, *kwargs)
+ .. method:: format(format_string, *args, **kwargs)
:meth:`format` is the primary API method. It takes a format template
string, and an arbitrary set of positional and keyword argument.
| Option | Meaning |
+=========+==========================================================+
| ``'<'`` | Forces the field to be left-aligned within the available |
- | | space (this is the default). |
+ | | space (this is the default for most objects). |
+---------+----------------------------------------------------------+
| ``'>'`` | Forces the field to be right-aligned within the |
- | | available space. |
+ | | available space (this is the default for numbers). |
+---------+----------------------------------------------------------+
| ``'='`` | Forces the padding to be placed after the sign (if any) |
| | but before the digits. This is used for printing fields |
Nesting arguments and more complex examples::
>>> for align, text in zip('<^>', ['left', 'center', 'right']):
- ... '{0:{align}{fill}16}'.format(text, fill=align, align=align)
+ ... '{0:{fill}{align}16}'.format(text, fill=align, align=align)
...
'left<<<<<<<<<<<<'
'^^^^^center^^^^^'
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