Python command Module Argparse learning notes (iv)

• Default parameters

Argumentparser.set_defaults (**kwargs)

Set_defaults () can set default values for some parameters

>>> parser = Argparse. Argumentparser () >>> parser.add_argument (' foo ', type=int) >>> parser.set_defaults (bar=123, baz= ' Test ') >>> Parser.parse_args ([' 456 ']) Namespace (bar=123, baz= ' test ', foo=456)

Default values at the parser level override default values at the parameter level

>>> parser = Argparse. Argumentparser () >>> parser.add_argument ('--foo ', default= ' bar ') >>> parser.set_defaults (foo= ' Test ') >>> Parser.parse_args ([]) Namespace (foo= ' test ')

The Get_defaults () method can get the default values set in Add_argument () and Set_defaults ()

>>> parser = Argparse. Argumentparser () >>> parser.add_argument ('--foo ', default= ' bar ') >>> parser.set_defaults (air= ' Test ') >>> parser.get_default (' air ') ' Test ' >>> parser.get_default (' foo ') ' Bar '

• Parameter section uses

If the script uses only a few parameters from the arguments passed, you can use the Parse_known_args () method to pass other arguments to other scripts.

Argumentparser.parse_known_args (Args=none, Namespace=none)

It works very much like Parse_args (), but instead of generating an error when an extra parameter is present, it returns a tuple and list that contains the fill namespace and the remaining argument string

Import Argparseparser = Argparse. Argumentparser () parser.add_argument (' Bar ') parser.add_argument ('-t ', '--thread ') args = Parser.parse_known_args () if Args:   print (args)

Run results

Prefix matching rules apply to Parse_known_args ()

Python command Module Argparse learning notes (iv)