argparse

问题 This might be a simple one. Assume I have a program that uses argparse to process command line arguments/options. The following will print the \'help\' message: ./myprogram -h or: ./myprogram --help But, if I run the script without any arguments whatsoever, it doesn\'t do anything. What I want it to do is to display the usage message when it is called with no arguments. How is that done? 回答1: This answer comes from Steven Bethard on Google groups. I'm reposting it here to make it easier for

问题 I\'m using Python 3.4, I\'m trying to use argparse with subparsers, and I want to have a similar behavior to the one in Python 2.x where if I don\'t supply a positional argument (to indicate the subparser/subprogram) I\'ll get a helpful error message. I.e., with python2 I\'ll get the following error message: $ python2 subparser_test.py usage: subparser_test.py [-h] {foo} ... subparser_test.py: error: too few arguments I\'m setting the required attribute as suggested in https://stackoverflow

问题 I\'m using argparse in Python 2.7 for parsing input options. One of my options is a multiple choice. I want to make a list in its help text, e.g. from argparse import ArgumentParser parser = ArgumentParser(description=\'test\') parser.add_argument(\'-g\', choices=[\'a\', \'b\', \'g\', \'d\', \'e\'], default=\'a\', help=\"Some option, where\\n\" \" a = alpha\\n\" \" b = beta\\n\" \" g = gamma\\n\" \" d = delta\\n\" \" e = epsilon\") parser.parse_args() However, argparse strips all newlines and

问题 I am trying to pass a list as an argument to a command line program. Is there an argparse option to pass a list as option? parser.add_argument(\'-l\', \'--list\', type=list, action=\'store\', dest=\'list\', help=\'<Required> Set flag\', required=True) Script is called like below python test.py -l \"265340 268738 270774 270817\" 回答1: TL;DR 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','

问题 I noticed that the Python 2.7 documentation includes yet another command-line parsing module. In addition to getopt and optparse we now have argparse . Why has yet another command-line parsing module been created? Why should I use it instead of optparse ? Are there new features that I should know about? 回答1: As of python 2.7 , optparse is deprecated, and will hopefully go away in the future. argparse is better for all the reasons listed on its original page (https://code.google.com/archive/p

问题 I have a script which is meant to be used like this: usage: installer.py dir [-h] [-v] dir is a positional argument which is defined like this: parser.add_argument(\'dir\', default=os.getcwd()) I want the dir to be optional: when it\'s not specified it should just be cwd . Unfortunately when I don\'t specify the dir argument, I get Error: Too few arguments . 回答1: Use nargs='?' (or nargs='*' if you will need more than one dir) parser.add_argument('dir', nargs='?', default=os.getcwd()) extended

问题 Is there a way to make argparse recognize anything between two quotes as a single argument? It seems to keep seeing the dashes and assuming that it\'s the start of a new option I have something like: mainparser = argparse.ArgumentParser() subparsers = mainparser.add_subparsers(dest=\'subcommand\') parser = subparsers.add_parser(\'queue\') parser.add_argument(\'-env\', \'--extraEnvVars\', type=str, help=\'String of extra arguments to be passed to model.\') ...other arguments added to parser...

问题 The documentation for the argparse python module, while excellent I\'m sure, is too much for my tiny beginner brain to grasp right now. I don\'t need to do math on the command line or meddle with formatting lines on the screen or change option characters. All I want to do is \"If arg is A, do this, if B do that, if none of the above show help and quit\" . 回答1: My understanding of the original question is two-fold. First, in terms of the simplest possible argparse example, I'm surprised that I

问题 I would like to use argparse to parse boolean command-line arguments written as \"--foo True\" or \"--foo False\". For example: my_program --my_boolean_flag False However, the following test code does not do what I would like: import argparse parser = argparse.ArgumentParser(description=\"My parser\") parser.add_argument(\"--my_bool\", type=bool) cmd_line = [\"--my_bool\", \"False\"] parsed_args = parser.parse(cmd_line) Sadly, parsed_args.my_bool evaluates to True . This is the case even when