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argparse.ArgumentDefaultsHelpFormatter

help formatters

A help formatter that appends each argument's default value to its help: '(default: 3)'. It saves you from repeating the default in the text by hand.

Syntax

argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter)

The default is appended only to arguments that have help: an argument without help gets no note even if it has a default. Arguments without a default show '(default: None)', which confuses users; if you write %(default)s into a help string yourself, the formatter will not add it a second time.

Examples

import argparse
parser = argparse.ArgumentParser(
    prog='app', formatter_class=argparse.ArgumentDefaultsHelpFormatter)
parser.add_argument('--n', type=int, default=3, help='сколько раз')
parser.add_argument('--name', default='x')
print(parser.format_help())  # → --n N        сколько раз (default: 3) / --name NAME

See also

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