Python argparse

https://pymotw.com/3/argparse/

argparse_action.py

import argparse

parser = argparse.ArgumentParser()

parser.add_argument('-s', action='store',
                    dest='simple_value',
                    help='Store a simple value')

parser.add_argument('-c', action='store_const',
                    dest='constant_value',
                    const='value-to-store',
                    help='Store a constant value')

parser.add_argument('-t', action='store_true',
                    default=False,
                    dest='boolean_t',
                    help='Set a switch to true')
parser.add_argument('-f', action='store_false',
                    default=True,
                    dest='boolean_f',
                    help='Set a switch to false')

parser.add_argument('-a', action='append',
                    dest='collection',
                    default=[],
                    help='Add repeated values to a list')

parser.add_argument('-A', action='append_const',
                    dest='const_collection',
                    const='value-1-to-append',
                    default=[],
                    help='Add different values to list')
parser.add_argument('-B', action='append_const',
                    dest='const_collection',
                    const='value-2-to-append',
                    help='Add different values to list')

parser.add_argument('--version', action='version',
                    version='%(prog)s 1.0')

results = parser.parse_args()
print('simple_value     = {!r}'.format(results.simple_value))
print('constant_value   = {!r}'.format(results.constant_value))
print('boolean_t        = {!r}'.format(results.boolean_t))
print('boolean_f        = {!r}'.format(results.boolean_f))
print('collection       = {!r}'.format(results.collection))
print('const_collection = {!r}'.format(results.const_collection))

The -t and -f options are configured to modify different option values, each storing either True or False. The dest values for -Aand -B are the same so that their constant values are appended to the same list.

$ python3 argparse_action.py -h

usage: argparse_action.py [-h] [-s SIMPLE_VALUE] [-c] [-t] [-f]
                          [-a COLLECTION] [-A] [-B] [--version]

optional arguments:
  -h, --help       show this help message and exit
  -s SIMPLE_VALUE  Store a simple value
  -c               Store a constant value
  -t               Set a switch to true
  -f               Set a switch to false
  -a COLLECTION    Add repeated values to a list
  -A               Add different values to list
  -B               Add different values to list
  --version        show program's version number and exit

$ python3 argparse_action.py -s value

simple_value     = 'value'
constant_value   = None
boolean_t        = False
boolean_f        = True
collection       = []
const_collection = []

$ python3 argparse_action.py -c

simple_value     = None
constant_value   = 'value-to-store'
boolean_t        = False
boolean_f        = True
collection       = []
const_collection = []

$ python3 argparse_action.py -t

simple_value     = None
constant_value   = None
boolean_t        = True
boolean_f        = True
collection       = []
const_collection = []

$ python3 argparse_action.py -f

simple_value     = None
constant_value   = None
boolean_t        = False
boolean_f        = False
collection       = []
const_collection = []

$ python3 argparse_action.py -a one -a two -a three

simple_value     = None
constant_value   = None
boolean_t        = False
boolean_f        = True
collection       = ['one', 'two', 'three']
const_collection = []

$ python3 argparse_action.py -B -A

simple_value     = None
constant_value   = None
boolean_t        = False
boolean_f        = True
collection       = []
const_collection = ['value-2-to-append', 'value-1-to-append']