New submission from py.user: https://docs.python.org/3/howto/argparse.html#combining-positional-and-optional-arguments "And, just like the “store_true” action, if you don’t specify the -v flag, that flag is considered to have None value."
This sentence is misleading. It supposes that "store_true" action can save None value. But "store_true" action always saves True or False value. An example: This code was taken from the argparse howto. I've just added the -f option and printed args to the stdout. a.py #!/usr/bin/env python3 import argparse parser = argparse.ArgumentParser() parser.add_argument("square", type=int, help="display the square of a given number") parser.add_argument("-v", "--verbosity", action="count", help="increase output verbosity") parser.add_argument("-f", "--flag", action="store_true") args = parser.parse_args() print('args:', args) The output in the console: [guest@localhost bugs]$ ./a.py 1 args: Namespace(flag=False, square=1, verbosity=None) [guest@localhost bugs]$ In the output we see that the -f option have got the False value not None. Applied a patch to the issue that just removes words about analogy with store_true action. ---------- assignee: docs@python components: Documentation, Library (Lib) files: argparse_store_true.diff keywords: patch messages: 274725 nosy: docs@python, py.user priority: normal severity: normal status: open title: In the argparse howto there is a misleading sentence about store_true type: behavior versions: Python 3.6 Added file: http://bugs.python.org/file44419/argparse_store_true.diff _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue27991> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com