Bug report
When running a command line program with the --help/-h flag with argparse, if another flag has multiple names and choices to pick from, the options are printed multiple times instead of just once. For example, the program below:
import argparse if __name__ == "__main__": parser = ArgumentParser() parser.add_argument('-m', '--metric', choices=["accuracy", "precision", "recall"]) parser.parse_args(["-h"])
Will print
usage: argparse_test.py [-h] [-m {accuracy,precision,recall}]
options:
-h, --help show this help message and exit
-m {accuracy,precision,recall}, --metric {accuracy,precision,recall}Notice that the flag choices are printed out twice, once for each flag name. This is redundant and negatively impacts readability. The program should output:
usage: argparse_test.py [-h] [-m {accuracy,precision,recall}]
options:
-h, --help show this help message and exit
-m, --metric {accuracy,precision,recall}Your environment
- CPython versions tested on: 3.10.6
- Operating system and architecture: Windows 11 with WSL 2
Linked PRs
- gh-101599: changed argparse -h/-help flag for the sake of readability #103372
- GH-101599: Update docs to remove redundant option in argparse tutorial #124025
- [3.12] GH-101599: Update docs to remove redundant option in argparse tutorial (GH-124025) #124036
- [3.13] GH-101599: Update docs to remove redundant option in argparse tutorial (GH-124025) #124037