Python module Argparse usage examples detailed

Argparse is a python built-in module for quick creation of command lines. There is a third-party module Click can also implement this function, both have advantages and disadvantages, look at the individual needs.

Official website

Https://docs.python.org/3.5/library/argparse.html

Import argparse__verison__ = ' 1.1.1 ' parser = argparse. Argumentparser (description= ' hahahaaaa ') parser.add_argument ('-V ', '--version ', action= ' version ', version= '% (Prog) s ' +__version__ ' parser.add_argument ('--name ', '-n ', metavar= ' Namemma ', dest= ' name ', type=str,help= ' your name ', Nargs=1 ) parser.add_argument ('-i ', metavar= ' III ', action= ' store_const ', dest= ' IIII ', const= ' II ', help= ' dfafsdf ') parser.add_ Argument ("-Z", choices=[' a ', ' B ', ' d '],required=false) parser.add_argument (' foo ') args = Parser.parse_args () print ( Type (args)) print (Args.name,args.iiii,args.foo)

Simple description of the Argumentparser parameter

Epilog-end text for command line help

Prog-(default:sys.argv[0]) program name, generally do not need to modify, in addition, if you need to use in Help to the program's name, you can use% (Prog) s

Prefix_chars-Prefix of the command, default is-, for example-f/--file. Some programs may want to support options such as/F and can use prefix_chars= "/"

Fromfile_prefix_chars-(Default:none) If you want the command line arguments to be read from the file, you may use it. For example, if fromfile_prefix_chars= ' @ ', there is a "@args. txt" in the command-line arguments, the contents of Args.txt are used as command-line arguments

Add_help-whether to add-h/-help option (default:true), general help information is required, so do not set it.

Add_argument: Read in command-line arguments, the call has multiple parameters

Argumentparser.add_argument (name or flags ...) [, Action] [, Nargs] [, Const] [, Default] [, type] [, Choices] [, Required] [, help] [, Metavar] [, Dest])

Name or flags: is a required parameter that accepts the option parameter or is a positional parameter (a string of file names)

Parameters without '--'

You must enter a value when invoking a script

The order of the parameter inputs is consistent with the order defined in the program

Parameters of '-'

Do not enter Add_argument ("-A")

Similar to the '--' shortname, but the variable name in the program is defined as the parameter name

'--' parameter

Parameter aliases: 1 characters only, case sensitive

Add_argument ("-shortname", "--name", help= "params means"), but cannot use ShortName in code

Dest: Parameter in the program corresponding variable name add_argument ("a", dest= ' Code_name ')

Default: Parameter defaults

Help: Parametric action interpretation add_argument ("a", help= "params means")

Type: Default string Add_argument ("C", Type=int)

Metavar: The name of the parameter, which is used only when displaying the help information.

Action

Store: The default action mode, which stores the value to the specified variable.

Store_const: The stored value is specified in the const portion of the parameter and is used to implement non-Boolean command-line flags.

Store_true/store_false: boolean switch. You can have 2 parameters corresponding to one variable.

Append: Stores the value into the list, which can be reused.

Append_const: Stores the value to the list and stores the value specified in the const portion of the parameter.

Count: Number of shorthand inputs for statistical parameters add_argument ("-C", "--GC", action= "Count")

Version output release information and then exit.

Const: Used with action= "Store_const|append_const", default value

Choices: The range of input values Add_argument ("--GB", choices=[' A ', ' B ', ' C ', 0])

Required: Normally-f options are optional, but if required=true is required

The Nsrgs is used to specify the number of parameters, which can be .... or * or +

? 0 or one

* 0 or more

+ one or more

Create a child parse, each of which corresponds to its own input parameter

Import argparse# sub-command functionsdef subcmd_list (args):   print  " List "def subcmd_create (args):   print " create "def subcmd_delete (args):    print  "Delete" Parser = argparse. Argumentparser () subparsers = parser.add_subparsers (help= ' commands ') # a list  Commandlist_parser = subparsers.add_parser (' list ',  help= ' listcontents ') list_parser.add_argument (' dirname ',  action= ' store ', help= ' directory tolist ') list_parse.set_defaults (func=subcmd_list) # A  create commandcreate_parser = subparsers.add_parser (' Create ',  help= ' Create a  directory ') create_parser.add_argument (' dirname ', action= ' store ', help= ' new directoryto create ') Create_parser.add_argument ('--read-only ', default=false, action= ' store_true ', help= ' Setpermissions to  prevent writing to the directory ') create_parser . Set_defaults (Func=subcmd_create) # a delete commanddelete_parser = subparsers.add_ Parser (' delete ', help= ' remove a directory ') delete_parser.add_argument (' dirname ',  action= ' store ', help= ' The directory to remove ') delete_parser.add_argument ('--recursive ',  '-R ', default= False, action= ' store_true ', help= ' Remove thecontents of the directory, too ') Delete_parser .set_defaults (Func=subcmd_delete) Args = parser.parse_args () # call  Subcmdargs.fun (args)

Use Help

# python Args_subparse.py-h
usage:args_subparse.py [-h] {Create,list,delete} ...

Positional arguments:
{Create,list,delete} commands
List listcontents
Create Create a directory
Delete Remove a directory

Optional arguments:
-H,--help show this help message and exit

# python args_subparse.py create-h
usage:args_subparse.py create [-h] [--read-only] DirName

Positional arguments:
DirName New Directoryto Create

Optional arguments:
-H,--help show this help message and exit
--read-only SetPermissions to prevent writing to the directory

# python args_subparse.py delete-h
usage:args_subparse.py Delete [-h] [--recursive] DirName

Positional arguments:
DirName the directory to remove

Optional arguments:
-H,--help show this help message and exit
--recursive,-R Remove thecontents of the directory, too

# python args_subparse.py list-h
usage:args_subparse.py list [-h] dirname

Positional arguments:
DirName Directory ToList

Optional arguments:
-H,--help show this help message and exit

Multiple subparser Use the same defined parameters

# Add_help=false, must be specified, otherwise quote-H repeats the definition Parents_parser = argparse. Argumentparser (Add_help=false) parents_parser.add_argument ('--foo ', dest= "foo", action= ' store_true ') parents_ Parser.add_argument ('--bar ', dest= "bar", action= ' Store_false ') parents_parser.add_argument ('--baz ', dest= "Baz", action= ' store_false ') parser = Argparse. Argumentparser () Subparsers = parser.add_subparsers (help= ' commands ') M_parser = Subparsers.add_parser ("MySQL", Parents=[parents_parser], help= "MySQL method") m_parser.set_defaults (func=sub_mysql) O_parser = subparsers.add_ Parser ("Oracle", Parents=[parents_parser], help= "Oracle Method") o_parser.set_defaults (func=sub_oracle) args = Parser.parse_args ()

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Python module Argparse usage examples detailed