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
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Python tracker <[email protected]>
<http://bugs.python.org/issue27991>
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