Python argparse choices with a default choice

Python argparse choices with a default choice

In the argparse module in Python, you can define a default choice for an argument by specifying its default parameter. However, when you use the choices parameter to restrict the argument to specific values, there is no built-in way to have a default choice that is not among the specified choices.

One common approach to achieve this is by defining a custom value for the default choice that serves as an indicator for using the default value. Here's how you can do it:

import argparse def main(args): print("Chosen option:", args.choice) if __name__ == "__main__": parser = argparse.ArgumentParser() parser.add_argument( "--choice", choices=["option1", "option2", "default"], # Include "default" as a choice default="default", # Set the default choice help="Choose an option (default: default)", ) args = parser.parse_args() main(args)

In this example, "default" is included as a choice and is also set as the default value. When you run the script without specifying the --choice option, it will use the default value "default".

When you need to check for the default choice in your code, you can compare the argument value with "default":

if args.choice == "default": print("Using the default choice") else: print("Chosen option:", args.choice)

This approach provides a way to use a default choice that is not among the specified choices while still allowing you to differentiate between the default and user-specified values.

Examples

  1. "Python argparse default choice with choices"

    Description: Explore how to specify a default choice among predefined options using Python's argparse module to enhance command-line interface usability.

    import argparse def main(): choices = ['option1', 'option2', 'option3'] parser = argparse.ArgumentParser(description="Example argparse default choice with choices") parser.add_argument("--choice", choices=choices, default='option1', help="Choose an option") args = parser.parse_args() print("Selected choice:", args.choice) if __name__ == "__main__": main()

  2. "Python argparse default option from choices"

    Description: Learn how to set a default option from a list of choices in Python argparse, providing a convenient default behavior for users.

    import argparse def main(): choices = ['red', 'green', 'blue'] parser = argparse.ArgumentParser(description="Example argparse default option from choices") parser.add_argument("--color", choices=choices, default='green', help="Choose a color") args = parser.parse_args() print("Selected color:", args.color) if __name__ == "__main__": main()

  3. "Python argparse default choice if not provided"

    Description: Understand how to specify a default choice in Python argparse when the user doesn't explicitly provide one, ensuring predictable behavior.

    import argparse def main(): choices = ['A', 'B', 'C'] parser = argparse.ArgumentParser(description="Example argparse default choice if not provided") parser.add_argument("--option", choices=choices, default='A', help="Choose an option") args = parser.parse_args() print("Selected option:", args.option) if __name__ == "__main__": main()

  4. "Python argparse default choice with options"

    Description: Discover how to set a default choice among specified options using Python's argparse module for streamlined command-line interactions.

    import argparse def main(): choices = ['yes', 'no'] parser = argparse.ArgumentParser(description="Example argparse default choice with options") parser.add_argument("--confirm", choices=choices, default='yes', help="Confirm action") args = parser.parse_args() print("Confirmation:", args.confirm) if __name__ == "__main__": main()

  5. "Python argparse default value from choices"

    Description: Learn how to assign a default value from a list of predefined choices in Python argparse, simplifying user input requirements.

    import argparse def main(): choices = ['option1', 'option2', 'option3'] parser = argparse.ArgumentParser(description="Example argparse default value from choices") parser.add_argument("--choice", choices=choices, default='option2', help="Choose an option") args = parser.parse_args() print("Selected choice:", args.choice) if __name__ == "__main__": main()

  6. "Python argparse default choice parameter"

    Description: Gain insights into setting a default choice parameter in Python argparse to streamline user input while still providing flexibility.

    import argparse def main(): choices = ['small', 'medium', 'large'] parser = argparse.ArgumentParser(description="Example argparse default choice parameter") parser.add_argument("--size", choices=choices, default='medium', help="Choose a size") args = parser.parse_args() print("Selected size:", args.size) if __name__ == "__main__": main()

  7. "Python argparse default option with choices list"

    Description: Learn how to define a default option from a list of choices using Python argparse, ensuring a predefined behavior when users don't specify an option.

    import argparse def main(): choices = ['option1', 'option2', 'option3'] parser = argparse.ArgumentParser(description="Example argparse default option with choices list") parser.add_argument("--choice", choices=choices, default='option3', help="Choose an option") args = parser.parse_args() print("Selected choice:", args.choice) if __name__ == "__main__": main()

  8. "Python argparse default choice for argument"

    Description: Discover how to set a default choice for a command-line argument in Python argparse, providing a convenient starting point for users.

    import argparse def main(): choices = ['cat', 'dog', 'bird'] parser = argparse.ArgumentParser(description="Example argparse default choice for argument") parser.add_argument("--animal", choices=choices, default='dog', help="Choose an animal") args = parser.parse_args() print("Selected animal:", args.animal) if __name__ == "__main__": main()

  9. "Python argparse default value from options"

    Description: Learn how to specify a default value from a predefined set of options in Python argparse to simplify user input requirements.

    import argparse def main(): choices = ['option1', 'option2', 'option3'] parser = argparse.ArgumentParser(description="Example argparse default value from options") parser.add_argument("--choice", choices=choices, default='option3', help="Choose an option") args = parser.parse_args() print("Selected choice:", args.choice) if __name__ == "__main__": main()

  10. "Python argparse default selection from choices"

    Description: Understand how to set a default selection from a list of choices in Python argparse, providing users with a preselected option for convenience.

    import argparse def main(): choices = ['option1', 'option2', 'option3'] parser = argparse.ArgumentParser(description="Example argparse default selection from choices") parser.add_argument("--choice", choices=choices, default='option2', help="Choose an option") args = parser.parse_args() print("Selected choice:", args.choice) if __name__ == "__main__": main()

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