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Diffstat (limited to 'Doc/library/optparse.rst')
-rw-r--r-- | Doc/library/optparse.rst | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/Doc/library/optparse.rst b/Doc/library/optparse.rst index add582e..6a03edf 100644 --- a/Doc/library/optparse.rst +++ b/Doc/library/optparse.rst @@ -273,7 +273,8 @@ You're free to define as many short option strings and as many long option strings as you like (including zero), as long as there is at least one option string overall. -The option strings passed to :meth:`add_option` are effectively labels for the +The option strings passed to :meth:`OptionParser.add_option` are effectively +labels for the option defined by that call. For brevity, we will frequently refer to *encountering an option* on the command line; in reality, :mod:`optparse` encounters *option strings* and looks up options from them. @@ -892,7 +893,8 @@ long option strings, but you must specify at least one overall option string. The canonical way to create an :class:`Option` instance is with the :meth:`add_option` method of :class:`OptionParser`. -.. method:: OptionParser.add_option(opt_str[, ...], attr=value, ...) +.. method:: OptionParser.add_option(option) + OptionParser.add_option(*opt_str, attr=value, ...) To define an option with only a short option string:: @@ -1165,6 +1167,17 @@ must specify for any option using that action. options.tracks.append(int("4")) + The ``append`` action calls the ``append`` method on the current value of the + option. This means that any default value specified must have an ``append`` + method. It also means that if the default value is non-empty, the default + elements will be present in the parsed value for the option, with any values + from the command line appended after those default values:: + + >>> parser.add_option("--files", action="append", default=['~/.mypkg/defaults']) + >>> opts, args = parser.parse_args(['--files', 'overrides.mypkg']) + >>> opts.files + ['~/.mypkg/defaults', 'overrides.mypkg'] + * ``"append_const"`` [required: :attr:`~Option.const`; relevant: :attr:`~Option.dest`] |