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authorÉric Araujo <merwok@netwok.org>2011-08-19 00:00:07 (GMT)
committerÉric Araujo <merwok@netwok.org>2011-08-19 00:00:07 (GMT)
commit67719bde07e3b4fccf8908ec19f4aa6feef6ee25 (patch)
treeabf5addfe6d05fbd19262f7ec7e06516431d10a2 /Doc
parentd9aeb60465f39a9d691bc0f7672bbe801852fd3b (diff)
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Synchronize argparse docs with 3.x versions
Diffstat (limited to 'Doc')
-rw-r--r--Doc/library/argparse.rst104
1 files changed, 52 insertions, 52 deletions
diff --git a/Doc/library/argparse.rst b/Doc/library/argparse.rst
index 08231411..d93c0d5 100644
--- a/Doc/library/argparse.rst
+++ b/Doc/library/argparse.rst
@@ -2,7 +2,7 @@
===============================================================================
.. module:: argparse
- :synopsis: Command-line option and argument-parsing library.
+ :synopsis: Command-line option and argument parsing library.
.. moduleauthor:: Steven Bethard <steven.bethard@gmail.com>
.. versionadded:: 2.7
.. sectionauthor:: Steven Bethard <steven.bethard@gmail.com>
@@ -103,9 +103,9 @@ or the :func:`max` function if it was not.
Parsing arguments
^^^^^^^^^^^^^^^^^
-:class:`ArgumentParser` parses args through the
+:class:`ArgumentParser` parses arguments through the
:meth:`~ArgumentParser.parse_args` method. This will inspect the command line,
-convert each arg to the appropriate type and then invoke the appropriate action.
+convert each argument to the appropriate type and then invoke the appropriate action.
In most cases, this means a simple :class:`Namespace` object will be built up from
attributes parsed out of the command line::
@@ -114,7 +114,7 @@ attributes parsed out of the command line::
In a script, :meth:`~ArgumentParser.parse_args` will typically be called with no
arguments, and the :class:`ArgumentParser` will automatically determine the
-command-line args from :data:`sys.argv`.
+command-line arguments from :data:`sys.argv`.
ArgumentParser objects
@@ -238,7 +238,7 @@ 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::
@@ -254,7 +254,7 @@ 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
@@ -267,7 +267,7 @@ 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.
@@ -389,7 +389,7 @@ 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::
@@ -415,7 +415,7 @@ 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`,
@@ -642,11 +642,11 @@ be positional::
action
^^^^^^
-:class:`ArgumentParser` objects associate command-line args with actions. These
-actions can do just about anything with the command-line args associated with
+:class:`ArgumentParser` objects associate command-line arguments with actions. These
+actions can do just about anything with the command-line arguments associated with
them, though most actions simply add an attribute to the object returned by
:meth:`~ArgumentParser.parse_args`. The ``action`` keyword argument specifies
-how the command-line args should be handled. The supported actions are:
+how the command-line arguments should be handled. The supported actions are:
* ``'store'`` - This just stores the argument's value. This is the default
action. For example::
@@ -718,8 +718,8 @@ the Action API. The easiest way to do this is to extend
:meth:`~ArgumentParser.parse_args`. Most actions add an attribute to this
object.
-* ``values`` - The associated command-line args, with any type-conversions
- applied. (Type-conversions are specified with the type_ keyword argument to
+* ``values`` - The associated command-line arguments, with any type conversions
+ applied. (Type conversions are specified with the type_ keyword argument to
:meth:`~ArgumentParser.add_argument`.
* ``option_string`` - The option string that was used to invoke this action.
@@ -751,7 +751,7 @@ 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 args 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()
@@ -763,11 +763,11 @@ values are:
Note that ``nargs=1`` produces a list of one item. This is different from
the default, in which the item is produced by itself.
-* ``'?'``. One arg will be consumed from the command line if possible, and
- produced as a single item. If no command-line arg is present, the value from
+* ``'?'``. One argument will be consumed from the command line if possible, and
+ produced as a single item. If no command-line argument is present, the value from
default_ will be produced. Note that for optional arguments, there is an
additional case - the option string is present but not followed by a
- command-line arg. In this case the value from const_ will be produced. Some
+ command-line argument. In this case the value from const_ will be produced. Some
examples to illustrate this::
>>> parser = argparse.ArgumentParser()
@@ -795,7 +795,7 @@ values are:
Namespace(infile=<open file '<stdin>', mode 'r' at 0x...>,
outfile=<open file '<stdout>', mode 'w' at 0x...>)
-* ``'*'``. All command-line args present are gathered into a list. Note that
+* ``'*'``. All command-line arguments present are gathered into a list. Note that
it generally doesn't make much sense to have more than one positional argument
with ``nargs='*'``, but multiple optional arguments with ``nargs='*'`` is
possible. For example::
@@ -809,7 +809,7 @@ values are:
* ``'+'``. Just like ``'*'``, all command-line args present are gathered into a
list. Additionally, an error message will be generated if there wasn't at
- least one command-line arg present. For example::
+ least one command-line argument present. For example::
>>> parser = argparse.ArgumentParser(prog='PROG')
>>> parser.add_argument('foo', nargs='+')
@@ -819,8 +819,8 @@ values are:
usage: PROG [-h] foo [foo ...]
PROG: error: too few arguments
-If the ``nargs`` keyword argument is not provided, the number of args consumed
-is determined by the action_. Generally this means a single command-line arg
+If the ``nargs`` keyword argument is not provided, the number of arguments consumed
+is determined by the action_. Generally this means a single command-line argument
will be consumed and a single item (not a list) will be produced.
@@ -837,9 +837,9 @@ the various :class:`ArgumentParser` actions. The two most common uses of it are
* When :meth:`~ArgumentParser.add_argument` is called with option strings
(like ``-f`` or ``--foo``) and ``nargs='?'``. This creates an optional
- argument that can be followed by zero or one command-line args.
+ argument that can be followed by zero or one command-line arguments.
When parsing the command line, if the option string is encountered with no
- command-line arg following it, the value of ``const`` will be assumed instead.
+ command-line argument following it, the value of ``const`` will be assumed instead.
See the nargs_ description for examples.
The ``const`` keyword argument defaults to ``None``.
@@ -851,7 +851,7 @@ default
All optional arguments and some positional arguments may be omitted at the
command line. The ``default`` keyword argument of
:meth:`~ArgumentParser.add_argument`, whose value defaults to ``None``,
-specifies what value should be used if the command-line arg is not present.
+specifies what value should be used if the command-line argument is not present.
For optional arguments, the ``default`` value is used when the option string
was not present at the command line::
@@ -862,8 +862,8 @@ was not present at the command line::
>>> parser.parse_args(''.split())
Namespace(foo=42)
-For positional arguments with nargs_ ``='?'`` or ``'*'``, the ``default`` value
-is used when no command-line arg was present::
+For positional arguments with nargs_ equal to ``?`` or ``*``, the ``default`` value
+is used when no command-line argument was present::
>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('foo', nargs='?', default=42)
@@ -887,12 +887,12 @@ command-line argument was not present.::
type
^^^^
-By default, ArgumentParser objects read command-line args in as simple strings.
-However, quite often the command-line string should instead be interpreted as
-another type, like a :class:`float`, :class:`int` or :class:`file`. The
+By default, :class:`ArgumentParser` objects read command-line arguments in as simple
+strings. However, quite often the command-line string should instead be
+interpreted as another type, like a :class:`float` or :class:`int`. The
``type`` keyword argument of :meth:`~ArgumentParser.add_argument` allows any
-necessary type-checking and type-conversions to be performed. Many common
-built-in types can be used directly as the value of the ``type`` argument::
+necessary type-checking and type conversions to be performed. Common built-in
+types and functions can be used directly as the value of the ``type`` argument::
>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('foo', type=int)
@@ -911,7 +911,7 @@ writable file::
Namespace(bar=<open file 'out.txt', mode 'w' at 0x...>)
``type=`` can take any callable that takes a single string argument and returns
-the type-converted value::
+the converted value::
>>> def perfect_square(string):
... value = int(string)
@@ -946,11 +946,11 @@ See the choices_ section for more details.
choices
^^^^^^^
-Some command-line args should be selected from a restricted set of values.
+Some command-line arguments should be selected from a restricted set of values.
These can be handled by passing a container object as the ``choices`` keyword
argument to :meth:`~ArgumentParser.add_argument`. When the command line is
-parsed, arg values will be checked, and an error message will be displayed if
-the arg was not one of the acceptable values::
+parsed, argument values will be checked, and an error message will be displayed if
+the argument was not one of the acceptable values::
>>> parser = argparse.ArgumentParser(prog='PROG')
>>> parser.add_argument('foo', choices='abc')
@@ -1053,7 +1053,7 @@ value as the "name" of each object. By default, for positional argument
actions, the dest_ value is used directly, and for optional argument actions,
the dest_ value is uppercased. So, a single positional argument with
``dest='bar'`` will that argument will be referred to as ``bar``. A single
-optional argument ``--foo`` that should be followed by a single command-line arg
+optional argument ``--foo`` that should be followed by a single command-line argument
will be referred to as ``FOO``. An example::
>>> parser = argparse.ArgumentParser()
@@ -1125,10 +1125,10 @@ 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::
@@ -1160,7 +1160,7 @@ The parse_args() method
created and how they are assigned. See the documentation for
:meth:`add_argument` for details.
- By default, the arg strings are taken from :data:`sys.argv`, and a new empty
+ By default, the argument strings are taken from :data:`sys.argv`, and a new empty
:class:`Namespace` object is created for the attributes.
@@ -1231,15 +1231,15 @@ 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 arg ``'-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')
@@ -1272,7 +1272,7 @@ 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::
@@ -1304,7 +1304,7 @@ An error is produced for arguments that could produce more than one options.
Beyond ``sys.argv``
^^^^^^^^^^^^^^^^^^^
-Sometimes it may be useful to have an ArgumentParser parse args other than those
+Sometimes it may be useful to have an ArgumentParser parse arguments other than those
of :data:`sys.argv`. This can be accomplished by passing a list of strings to
:meth:`~ArgumentParser.parse_args`. This is useful for testing at the
interactive prompt::
@@ -1390,7 +1390,7 @@ Sub-commands
>>> parser_b = subparsers.add_parser('b', help='b help')
>>> parser_b.add_argument('--baz', choices='XYZ', help='baz help')
>>>
- >>> # parse some arg lists
+ >>> # parse some argument lists
>>> parser.parse_args(['a', '12'])
Namespace(bar=12, foo=False)
>>> parser.parse_args(['--foo', 'b', '--baz', 'Z'])
@@ -1399,8 +1399,8 @@ 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
@@ -1522,7 +1522,7 @@ FileType objects
The :class:`FileType` factory creates objects that can be passed to the type
argument of :meth:`ArgumentParser.add_argument`. Arguments that have
- :class:`FileType` objects as their type will open command-line args as files
+ :class:`FileType` objects as their type will open command-line arguments as files
with the requested modes and buffer sizes:
>>> parser = argparse.ArgumentParser()
@@ -1636,7 +1636,7 @@ Parser defaults
.. method:: ArgumentParser.set_defaults(**kwargs)
Most of the time, the attributes of the object returned by :meth:`parse_args`
- will be fully determined by inspecting the command-line args and the argument
+ will be fully determined by inspecting the command-line arguments and the argument
actions. :meth:`set_defaults` allows some additional
attributes that are determined without any inspection of the command line to
be added::