argparse

Argparse: Required arguments listed under “optional arguments”?

by

Parameters starting with – or — are usually considered optional. All other parameters are positional parameters and as such required by design (like positional function arguments). It is possible to require optional arguments, but this is a bit against their design. Since they are still part of the non-positional arguments, they will still be listed … Read more

Argparse: Way to include default values in ‘–help’?

by

Use the argparse.ArgumentDefaultsHelpFormatter formatter: parser = argparse.ArgumentParser( # … other options … formatter_class=argparse.ArgumentDefaultsHelpFormatter) To quote the documentation: The other formatter class available, ArgumentDefaultsHelpFormatter, will add information about the default value of each of the arguments. Note that this only applies to arguments that have help text defined; with no help value for an argument, there … Read more

Python argparse command line flags without arguments

by

As you have it, the argument w is expecting a value after -w on the command line. If you are just looking to flip a switch by setting a variable True or False, have a look here (specifically store_true and store_false) import argparse parser = argparse.ArgumentParser() parser.add_argument(‘-w’, action=’store_true’) where action=’store_true’ implies default=False. Conversely, you could … Read more

Simple argparse example wanted: 1 argument, 3 results

by

Here’s the way I do it with argparse (with multiple args): parser = argparse.ArgumentParser(description=’Description of your program’) parser.add_argument(‘-f’,’–foo’, help=’Description for foo argument’, required=True) parser.add_argument(‘-b’,’–bar’, help=’Description for bar argument’, required=True) args = vars(parser.parse_args()) args will be a dictionary containing the arguments: if args[‘foo’] == ‘Hello’: # code here if args[‘bar’] == ‘World’: # code here In … Read more

How can I pass a list as a command-line argument with argparse?

by

SHORT ANSWER Use the nargs option or the ‘append’ setting of the action option (depending on how you want the user interface to behave). nargs parser.add_argument(‘-l’,’–list’, nargs=”+”, help='<Required> Set flag’, required=True) # Use like: # python arg.py -l 1234 2345 3456 4567 nargs=”+” takes 1 or more arguments, nargs=”*” takes zero or more. append parser.add_argument(‘-l’,’–list’, … Read more

Argparse optional positional arguments?

by

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) >>> … Read more

Parsing boolean values with argparse

by

I think a more canonical way to do this is via: command –feature and command –no-feature argparse supports this version nicely: Python 3.9+: parser.add_argument(‘–feature’, action=argparse.BooleanOptionalAction) Python < 3.9: parser.add_argument(‘–feature’, action=’store_true’) parser.add_argument(‘–no-feature’, dest=”feature”, action=’store_false’) parser.set_defaults(feature=True) Of course, if you really want the –arg <True|False> version, you could pass ast.literal_eval as the “type”, or a user defined … Read more

tech