diff options
-rw-r--r-- | Doc/library/argparse.rst | 34 |
1 files changed, 17 insertions, 17 deletions
diff --git a/Doc/library/argparse.rst b/Doc/library/argparse.rst index b58a58c..38e52fb 100644 --- a/Doc/library/argparse.rst +++ b/Doc/library/argparse.rst @@ -244,7 +244,7 @@ This can be achieved by passing ``False`` as the ``add_help=`` argument to --foo FOO foo help The help option is typically ``-h/--help``. The exception to this is -if the ``prefix_chars=`` is specified and does not include ``'-'``, in +if the ``prefix_chars=`` is specified and does not include ``-``, in which case ``-h`` and ``--help`` are not valid options. In this case, the first character in ``prefix_chars`` is used to prefix the help options:: @@ -260,7 +260,7 @@ the help options:: prefix_chars ^^^^^^^^^^^^ -Most command-line options will use ``'-'`` as the prefix, e.g. ``-f/--foo``. +Most command-line options will use ``-`` as the prefix, e.g. ``-f/--foo``. Parsers that need to support different or additional prefix characters, e.g. for options like ``+f`` or ``/foo``, may specify them using the ``prefix_chars=`` argument @@ -273,7 +273,7 @@ to the ArgumentParser constructor:: Namespace(bar='Y', f='X') The ``prefix_chars=`` argument defaults to ``'-'``. Supplying a set of -characters that does not include ``'-'`` will cause ``-f/--foo`` options to be +characters that does not include ``-`` will cause ``-f/--foo`` options to be disallowed. @@ -395,7 +395,7 @@ epilog_ texts in command-line help messages:: likewise for this epilog whose whitespace will be cleaned up and whose words will be wrapped across a couple lines -Passing :class:`~argparse.RawDescriptionHelpFormatter` as ``formatter_class=`` +Passing :class:`RawDescriptionHelpFormatter` as ``formatter_class=`` indicates that description_ and epilog_ are already correctly formatted and should not be line-wrapped:: @@ -421,7 +421,7 @@ should not be line-wrapped:: optional arguments: -h, --help show this help message and exit -:class:`RawTextHelpFormatter` maintains whitespace for all sorts of help text +:class:`RawTextHelpFormatter` maintains whitespace for all sorts of help text, including argument descriptions. The other formatter class available, :class:`ArgumentDefaultsHelpFormatter`, @@ -759,7 +759,7 @@ single action to be taken. The ``nargs`` keyword argument associates a different number of command-line arguments with a single action. The supported values are: -* N (an integer). N arguments from the command line will be gathered together into a +* ``N`` (an integer). ``N`` arguments from the command line will be gathered together into a list. For example:: >>> parser = argparse.ArgumentParser() @@ -870,7 +870,7 @@ was not present at the command line:: >>> parser.parse_args(''.split()) Namespace(foo=42) -For positional arguments with nargs_ ``='?'`` or ``'*'``, the ``default`` value +For positional arguments with nargs_ equal to ``?`` or ``*``, the ``default`` value is used when no command-line argument was present:: >>> parser = argparse.ArgumentParser() @@ -1133,10 +1133,10 @@ attribute is determined by the ``dest`` keyword argument of For optional argument actions, the value of ``dest`` is normally inferred from the option strings. :class:`ArgumentParser` generates the value of ``dest`` by -taking the first long option string and stripping away the initial ``'--'`` +taking the first long option string and stripping away the initial ``--`` string. If no long option strings were supplied, ``dest`` will be derived from -the first short option string by stripping the initial ``'-'`` character. Any -internal ``'-'`` characters will be converted to ``'_'`` characters to make sure +the first short option string by stripping the initial ``-`` character. Any +internal ``-`` characters will be converted to ``_`` characters to make sure the string is a valid attribute name. The examples below illustrate this behavior:: @@ -1239,15 +1239,15 @@ it exits and prints the error along with a usage message:: PROG: error: extra arguments found: badger -Arguments containing ``"-"`` -^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +Arguments containing ``-`` +^^^^^^^^^^^^^^^^^^^^^^^^^^ The :meth:`~ArgumentParser.parse_args` method attempts to give errors whenever the user has clearly made a mistake, but some situations are inherently -ambiguous. For example, the command-line argument ``'-1'`` could either be an +ambiguous. For example, the command-line argument ``-1`` could either be an attempt to specify an option or an attempt to provide a positional argument. The :meth:`~ArgumentParser.parse_args` method is cautious here: positional -arguments may only begin with ``'-'`` if they look like negative numbers and +arguments may only begin with ``-`` if they look like negative numbers and there are no options in the parser that look like negative numbers:: >>> parser = argparse.ArgumentParser(prog='PROG') @@ -1280,7 +1280,7 @@ there are no options in the parser that look like negative numbers:: usage: PROG [-h] [-1 ONE] [foo] PROG: error: argument -1: expected one argument -If you have positional arguments that must begin with ``'-'`` and don't look +If you have positional arguments that must begin with ``-`` and don't look like negative numbers, you can insert the pseudo-argument ``'--'`` which tells :meth:`~ArgumentParser.parse_args` that everything after that is a positional argument:: @@ -1407,8 +1407,8 @@ Sub-commands Note that the object returned by :meth:`parse_args` will only contain attributes for the main parser and the subparser that was selected by the command line (and not any other subparsers). So in the example above, when - the ``"a"`` command is specified, only the ``foo`` and ``bar`` attributes are - present, and when the ``"b"`` command is specified, only the ``foo`` and + the ``a`` command is specified, only the ``foo`` and ``bar`` attributes are + present, and when the ``b`` command is specified, only the ``foo`` and ``baz`` attributes are present. Similarly, when a help message is requested from a subparser, only the help |