argparse

问题 I am using argparse to parse command line arguments and by default on receiving invalid arguments it prints help message and exit. Is it possible to customize the behavior of argparse when it receives invalid arguments? Generally I want to catch all invalid arguments and do stuff with them. I am looking for something like: parser = argparse.ArgumentParser() # add some arguments here try: parser.parse_args() except InvalidArgvsError, iae: print "handle this invalid argument '{arg}' my way!"

问题 I'm using the argparse module to get two optional command line arguments: parser.add_argument('start_date', nargs='?', metavar='START DATE', help='start date in YYYY-MM-DD') parser.add_argument('end_date', nargs='?', metavar='END DATE', help='end date in YYYY-MM-DD') which gives > python test_arg.py -h usage: test_arg.py [-h] [START DATE] [END DATE] However I want the pair of optional arguments ( START DATE and END DATE ), if provided at all, to be provided together. Something like along this

问题 I'm using the argparse module to get two optional command line arguments: parser.add_argument('start_date', nargs='?', metavar='START DATE', help='start date in YYYY-MM-DD') parser.add_argument('end_date', nargs='?', metavar='END DATE', help='end date in YYYY-MM-DD') which gives > python test_arg.py -h usage: test_arg.py [-h] [START DATE] [END DATE] However I want the pair of optional arguments ( START DATE and END DATE ), if provided at all, to be provided together. Something like along this

问题 I have an object A which contains parserA - an argparse.ArgumentParser object There is also object B which contains parserB - another argparse.ArgumentParser Object A contains an instance of object B, however object B's arguments now need to be parsed by the parser in object A (since A is the one being called from the command line with the arguments, not B) Is there a way to write in Python object A: parserA += B.parserB? 回答1: argparse was developed around objects. Other than a few constants

问题 I have to write a command-line interface and I've seen I can use docopt and argparse . I would like to know what are the main differences between the two so that I can make an enlightened choice. Please stick to the facts. I don't want Wow. docopt. So beautiful. Very useful. 回答1: Docopt parses a doc string, whereas argparse constructs its parsing by creating an object instance and adding behaviour to it by function calls. Example for argparse: parser = argparse.ArgumentParser() parser.add

问题 My command line utility should accept several filters attached to each other (similar to Unix pipeline). Each filter has a number of options. For example chain filter currently has the following options: -t NAMESPACE, --target NAMESPACE target namespace(s) -s {precedence,doc}, --next-script {precedence,doc} "next script" algorithm ("precedence" is not supported) -n {ignore,remove,error}, --not-in-target {ignore,remove,error} what if a result is not in target NS -u URL, --universal-precedence

问题 If I create a subparser with a specific help string, this string is not displayed when the user runs myprog command --help : parser = argparse.ArgumentParser() subparsers = parser.add_subparsers(help="sub-command help") parser_command = subparsers.add_parser("command", help="Issue a command") parser.parse_args() The top-level help shows this command subcommand with the description "Issue a command" alongside: $ python prog.py --help usage: prog.py [-h] {command} ... positional arguments:

问题 I have the following python program: #!/usr/bin/env python import argparse parser = argparse.ArgumentParser() parser.add_argument('arg', choices=['foo', 'bar', 'baz'], default='foo', nargs='*') args = parser.parse_args() print(args) If I invoke the program like this: ./prog.py the output is Namespace(arg='foo') But if I invoke the program with foo as an argument: ./prog.py foo the output is Namespace(arg=['foo']) Question How can I get arg 's default value to become a list ? I've tried I've

问题 I've got a simple python script in file 'bin/test': #!/usr/bin/env python import argparse PROGRAM_NAME = "name" PROGRAM_VERSION = "0.0.1" PROGRAM_DESCRIPTION = "desc" parser = argparse.ArgumentParser(prog=PROGRAM_NAME, description=PROGRAM_DESCRIPTION) parser.add_argument('--version', action='version', version='%(prog)s ' + PROGRAM_VERSION) args = parser.parse_args() When I run it with the --version param, or --help , it prints everything OK: $ bin/test --version name 0.0.1 $ bin/test --help

问题 Can I open a gzip file directly with argparse by changing the type=argparse.FileType() to some gzip type? It's not in the docs, so I'm not sure if argparse even suppoets compressed file types... 回答1: First, the type parameter is a function or other callable that converts a string into something else. That's all. argparse.FileType is factory class that ends up doing something close to: def filetype(astring): mode = 'r' # or 'w' etc. try: f = open(astring, mode) except IOError: raise argparse