argparse

问题 I've upgraded to Python 3.4.2 and argparse (from optparse) but neither appears to recognise command line options. As a simple test I run this; #test_argparse.py def main(): import argparse parser = argparse.ArgumentParser(description='Execute database query.') parser.add_argument("-q", "--query", dest="query", help="Name of the query file to be run") args = parser.parse_args() print(args) if __name__ == '__main__': main() From the command line, when I run test_argparse.py -q get_msre_for_book

问题 I am trying to obtain a string of numbers from argparse. It's optional whether or not the argument -n is provided. import argparse parser = argparse.ArgumentParser() parser.add_argument('-n', nargs=1) # -n is optional but must come with one and only one argument args = parser.parse_args() test = args.n if test != 'None': print("hi " + test) The program fails when I do not provide "-n argument", but works fine when I do. Traceback (most recent call last): File "parse_args_test.py", line 7, in

问题 From what I understand from another SO post, to unittest a script that takes command line arguments through argparse, I should do something like the code below, giving sys.argv[0] as arg. import unittest import match_loc class test_method_main(unittest.TestCase): loc = match_loc.main() self.assertEqual(loc, [4]) if __name__ == '__main__': sys.argv[1] = 'aaaac' sys.argv[2] = 'ac' unittest.main(sys.argv[0]) This returns the error: usage: test_match_loc.py [-h] text patterns [patterns ...] test

问题 When I give Python's argparse input it doesn't like, it raises a SystemExit with a code of 2, which seems to mean "No such file or directory". Why use this error code? import argparse import errno parser = argparse.ArgumentParser() parser.add_argument('arg') try: parser.parse_args([]) except SystemExit as se: print("Got error code {} which is {} in errno" .format(se.code, errno.errorcode[se.code])) produces this output: usage: se.py [-h] arg se.py: error: too few arguments Got error code 2

问题 I would like to modify my help option in project I created. I put argparse in manage.py file, like this parser = argparse.ArgumentParser( description="Some desc", formatter_class=argparse.RawTextHelpFormatter ) args = parser.parse_args() print(args) if __name__ == "__main__": os.environ.setdefault("DJANGO_SETTINGS_MODULE", "Reporter.settings") try: from django.core.management import execute_from_command_line except ImportError: # The above import may fail for some other reason. Ensure that

问题 I am writing unit tests for a Python library using pytest I need to specify a directory for test files to avoid automatic test file discovery, because there is a large sub-directory structure, including many files in the library containing "_test" or "test_" in the name but are not intended for pytest Some files in the library use argparse for specifying command-line options The problem is that specifying the directory for pytest as a command-line argument seems to interfere with using

问题 I'd like to print all options of the program and they are grouped for readability. However when accessing the arguments via vars(args) , the order is random. 回答1: argparse parses the list of arguments in sys.argv[1:] ( sys.argv[0] is used as the prog value in usage ). args=parser.parse_args() returns a argparse.Namespace object. vars(args) returns a dictionary based on this object ( args.__dict__ ). Keys of a dictionary are unordered. print(args) also uses this dictionary order. The parser

问题 This code works properly to increase the width of the help text, but it's unclear. What is the lambda function doing? EDIT: To clarify, the question is not Why are lambda functions useful in general , but instead, how is the argument parser init code using the lambda function ? import argparse import sys formatter = lambda prog: argparse.HelpFormatter(prog, width=100) dummy_text = """Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore

问题 In a file (say parser.py ) I have: import argparse def parse_cmdline(cmdline=None): parser = argparse.ArgumentParser() parser.add_argument('--first-param',help="Does foo.") parser.add_argument('--second-param',help="Does bar.") if cmdline is not None: args = parser.parse_args(cmdline) else: args = parser.parse_args() return vars(args) if __name__=='__main__': print parse_cmdline() Sure enough, when called from the command line it works and give me pretty much what I expect: $ ./parser.py -

问题 Let's say I have two groups of arguments. You can use any number of arguments from each group but you cannot mix arguments between the groups. Is there a way to customize conflicting arguments in argparse module? I've tried using method add_mutually_exclusive_group but it's not what I'm looking for. 回答1: I've proposed a patch (or rather patches) that would let you test for general logical combinations of arguments. http://bugs.python.org/issue11588 . The core of my ideas there is to add a