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How do you group related arguments visually in the generated --help output using argument groups?

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Answer

add_argument_group() creates a labeled section within the parser's help output, letting you organize related arguments (like all authentication-related flags) together for readability, WITHOUT changing how the arguments are actually parsed — it's purely a --help display organization feature.
parser = argparse.ArgumentParser()
auth_group = parser.add_argument_group("authentication")
auth_group.add_argument("--username")
auth_group.add_argument("--password")

output_group = parser.add_argument_group("output options")
output_group.add_argument("--format", choices=["json", "csv"])
# --help now shows these grouped under their respective section headers
Real-world example Organizing a CLI tool's --help output into clear, logical sections (authentication, output, filtering) for a large number of flags.

Common follow-ups: Does argument grouping have any effect on argument PARSING behavior, or is it purely cosmetic for --help?

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All 15 Command-Line Interfaces (argparse) questions