Python's command parsing module optparse

Example

From Optparse import optionparser[...]def Main (): Usage ="Usage:%prog [options] arg"Parser = Optionparser (usage) parser.add_option ("-F","--file", dest="FileName", help="read data from FILENAME") Parser.add_option ("-V","--verbose", action="Store_true", dest="Verbose") Parser.add_option ("-Q","--quiet", action="Store_false", dest="Verbose")    [...] (options, args) = Parser.parse_args ()ifLen (args)! =1: Parser.error ("Incorrect number of arguments")ifOptions.verbose:print"Reading%s ..."% Options.filename [...]if__name__ = ="__main__": Main ()

Add option (Add_option ())

...)

Define short options
Parser.add_option ("-F", Attr=value, ...)

Define long options
Parser.add_option ("–foo", Attr=value, ...)

If you define

?parser.add_option("-f""--file", action="store"type="string", dest="filename")

The command line format can have the following form

-ffoo-f foo--file=foo--file foo

Results after parsing
Options.filename = "Foo"

Parsing (Parse_args ())

(options, args) = Parser.parse_args ()

Options parsed parameters, saved in dictionary form
Args cannot parse parameters, save as a list

Behavior (Action)

• Store default behavior, save value to Dest

• "Store_const" Saving constants

• "Append" append this option ' s argument to a list

• "Count" increment a counter by one

• "Callback" call a specified function

Set defaults (default)

parser.add_option("-v", action="store_true", dest="verbose"default=True)parser.set_defaults(verbose=True)

Generate Help Tips

The Help option is available and can be printed with parser.print_help ()
Parser.add_option ("-F", "–file", dest= "filename", help= "write report to File", metavar= "file")

Set a Boolean value

Supports Store_true and store_false two behaviors

parser.add_option("-v", action="store_true", dest="verbose")parser.add_option("-q", action="store_false", dest="verbose")

If you encounter-v,verbose=true, if you encounter-q,verbose=false

Error handling

(options, args) = parser.parse_args()[...]if options.a and options.b:    parser.error("options -a and -b are mutually exclusive")

Option group (Grouping options)

The format is as follows
Class Optparse. OptionGroup (parser, title, Description=none)

group"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)

The prompt results are as follows

Usage:<yourscript> [options] arg1 arg2Options:-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.

Python's command parsing module optparse