Argparse optional positional arguments?

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Use nargs="?" (or nargs="*" if you need more than one dir)

parser.add_argument('dir', nargs="?", default=os.getcwd())

extended example:

>>> import os, argparse
>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('-v', action='store_true')
_StoreTrueAction(option_strings=['-v'], dest="v", nargs=0, const=True, default=False, type=None, choices=None, help=None, metavar=None)
>>> parser.add_argument('dir', nargs="?", default=os.getcwd())
_StoreAction(option_strings=[], dest="dir", nargs="?", const=None, default="/home/vinay", type=None, choices=None, help=None, metavar=None)
>>> parser.parse_args('somedir -v'.split())
Namespace(dir="somedir", v=True)
>>> parser.parse_args('-v'.split())
Namespace(dir="/home/vinay", v=True)
>>> parser.parse_args(''.split())
Namespace(dir="/home/vinay", v=False)
>>> parser.parse_args(['somedir'])
Namespace(dir="somedir", v=False)
>>> parser.parse_args('somedir -h -v'.split())
usage: [-h] [-v] [dir]

positional arguments:
  dir

optional arguments:
  -h, --help  show this help message and exit
  -v

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