The following option attributes may be passed as keyword arguments
to parser.add_option()
. If you pass an option attribute
that is not relevant to a particular option, or fail to pass a required
option attribute, optparse raises OptionError.
"store"
)
Determines optparse's behaviour when this option is seen on the command line; the available options are documented above.
"string"
)
The argument type expected by this option (e.g., "string"
or
"int"
); the available option types are documented below.
If the option's action implies writing or modifying a value somewhere,
this tells optparse where to write it: dest names an attribute of the
options
object that optparse builds as it parses the command line.
default
(deprecated)
The value to use for this option's destination if the option is not
seen on the command line. Deprecated; use parser.set_defaults()
instead.
nargs
(default: 1)
How many arguments of type type should be consumed when this option is seen. If > 1, optparse will store a tuple of values to dest.
const
For actions that store a constant value, the constant value to store.
choices
For options of type "choice"
, the list of strings the user
may choose from.
callback
For options with action "callback"
, the callable to call when this
option is seen. See section 14.3.4, Option Callbacks for detail on the arguments
passed to callable
.
callback_args
, callback_kwargs
Additional positional and keyword arguments to pass to callback
after the four standard callback arguments.
Help text to print for this option when listing all available options
after the user supplies a help option (such as "-help"
).
If no help text is supplied, the option will be listed without help
text. To hide this option, use the special value SUPPRESS_HELP
.
metavar
(default: derived from option strings)
Stand-in for the option argument(s) to use when printing help text. See section 14.3.2, the tutorial for an example.
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