How to add command line arguments with flags in Python?

How to add command line arguments with flags in Python?

In Python, you can add command-line arguments with flags (also known as options or switches) using the argparse module, which provides a robust and flexible way to parse command-line arguments. Here's how to do it:

  1. Import the argparse module:

    import argparse

  2. Create an ArgumentParser object:

    parser = argparse.ArgumentParser(description='Description of your program')

    Replace 'Description of your program' with a brief description of what your program does.

  3. Add command-line arguments with flags using the add_argument method:

    parser.add_argument('-f', '--file', type=str, help='Input file path') parser.add_argument('-v', '--verbose', action='store_true', help='Enable verbose mode') parser.add_argument('-n', '--number', type=int, default=5, help='A number argument (default: 5)')
    • -f and --file are flags for specifying an input file path as a string.
    • -v and --verbose are boolean flags (use action='store_true') to enable verbose mode.
    • -n and --number are flags for specifying an integer argument with a default value of 5.

  4. Parse the command-line arguments:

    args = parser.parse_args()

  5. Access the parsed arguments in your code:

    if args.file: print(f'Input file: {args.file}') if args.verbose: print('Verbose mode enabled') print(f'Number argument: {args.number}')

    You can access the arguments using args.flag_name. For example, args.file would contain the file path provided with the -f or --file flag.

  6. Run your script with command-line arguments:

    python your_script.py -f input.txt -v -n 10

    Replace your_script.py with the name of your Python script and provide the desired command-line arguments.

This is a basic example of how to add and use command-line arguments with flags in Python using the argparse module. It allows you to create command-line interfaces for your Python scripts with structured and user-friendly argument handling.

Examples

  1. "Python argparse tutorial" Description: This search query is for those who want to learn how to use the argparse module in Python to handle command-line arguments effectively.

    import argparse def main(): parser = argparse.ArgumentParser(description='Process some integers.') parser.add_argument('integers', metavar='N', type=int, nargs='+', help='an integer for the accumulator') parser.add_argument('--sum', dest='accumulate', action='store_const', const=sum, default=max, help='sum the integers (default: find the max)') args = parser.parse_args() print(args.accumulate(args.integers)) if __name__ == '__main__': main()

  2. "Python command line flags example" Description: This query leads to examples demonstrating how to use flags (or options) in Python command-line programs using the argparse module.

    import argparse def main(): parser = argparse.ArgumentParser(description='Process some integers.') parser.add_argument('--verbose', '-v', action='store_true', help='increase output verbosity') args = parser.parse_args() if args.verbose: print('Verbosity turned on') else: print('Verbosity turned off') if __name__ == '__main__': main()

  3. "Python argparse optional argument" Description: This query aims to find information on how to define optional arguments with argparse in Python command-line applications.

    import argparse def main(): parser = argparse.ArgumentParser() parser.add_argument('--optional', '-o', help='optional argument') args = parser.parse_args() if args.optional: print('Optional argument:', args.optional) else: print('Optional argument not provided') if __name__ == '__main__': main()

  4. "Python argparse positional argument" Description: This query focuses on finding resources related to defining positional arguments using argparse in Python scripts.

    import argparse def main(): parser = argparse.ArgumentParser() parser.add_argument('positional', help='positional argument') args = parser.parse_args() print('Positional argument:', args.positional) if __name__ == '__main__': main()

  5. "Python argparse boolean flag" Description: This query helps users find information on how to define boolean flags (true/false options) with argparse in Python command-line applications.

    import argparse def main(): parser = argparse.ArgumentParser() parser.add_argument('--flag', '-f', action='store_true', help='boolean flag') args = parser.parse_args() if args.flag: print('Flag is set') else: print('Flag is not set') if __name__ == '__main__': main()

  6. "Python argparse required argument" Description: This query seeks information on how to define required arguments with argparse in Python scripts.

    import argparse def main(): parser = argparse.ArgumentParser() parser.add_argument('required', help='required argument') args = parser.parse_args() print('Required argument:', args.required) if __name__ == '__main__': main()

  7. "Python argparse multiple flags" Description: This query is for users interested in learning how to define and handle multiple flags (options) using argparse in Python.

    import argparse def main(): parser = argparse.ArgumentParser() parser.add_argument('--flag1', '-f1', action='store_true', help='first flag') parser.add_argument('--flag2', '-f2', action='store_true', help='second flag') args = parser.parse_args() if args.flag1: print('Flag 1 is set') if args.flag2: print('Flag 2 is set') if __name__ == '__main__': main()

  8. "Python argparse default value" Description: This query is for finding resources related to setting default values for arguments using argparse in Python scripts.

    import argparse def main(): parser = argparse.ArgumentParser() parser.add_argument('--optional', '-o', default='default', help='optional argument with default value') args = parser.parse_args() print('Optional argument:', args.optional) if __name__ == '__main__': main()

  9. "Python argparse help message" Description: This query is for those seeking information on how to customize and display help messages using argparse in Python.

    import argparse def main(): parser = argparse.ArgumentParser(description='Custom help message') parser.add_argument('--option', '-o', help='help message for option') args = parser.parse_args() print('Option:', args.option) if __name__ == '__main__': main()

  10. "Python argparse subcommands example" Description: This query leads to examples demonstrating how to implement subcommands using argparse in Python command-line applications.

    import argparse def foo(args): print('Running foo subcommand') def bar(args): print('Running bar subcommand') def main(): parser = argparse.ArgumentParser() subparsers = parser.add_subparsers() parser_foo = subparsers.add_parser('foo') parser_foo.set_defaults(func=foo) parser_bar = subparsers.add_parser('bar') parser_bar.set_defaults(func=bar) args = parser.parse_args() args.func(args) if __name__ == '__main__': main()

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