[issue27497] csv module: Add return value to DictWriter.writeheader
MICHAEL BLAHAY added the comment: I would like to drive this to conclusion since it appears this issue has not had any real activity in a while. First thing that needs to be determined is whether this enhancement is still desirable. Who can answer this? -- nosy: +MICHAEL BLAHAY ___ Python tracker <https://bugs.python.org/issue27497> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue27497] csv module: Add return value to DictWriter.writeheader
MICHAEL BLAHAY added the comment: Ah ha, so there is. I'm glad this one will get closed out. Sorry for noob mistake. -- ___ Python tracker <https://bugs.python.org/issue27497> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue11698] Improve repr for structseq objects to show named, but unindexed fields
MICHAEL BLAHAY added the comment: I will work on this -- nosy: +MICHAEL BLAHAY ___ Python tracker <https://bugs.python.org/issue11698> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue36582] collections.UserString encode method returns a string
MICHAEL BLAHAY added the comment: I will pick this on up -- nosy: +MICHAEL BLAHAY ___ Python tracker <https://bugs.python.org/issue36582> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue36582] collections.UserString encode method returns a string
MICHAEL BLAHAY added the comment: My mistake, dfortunov is already working on this one. -- ___ Python tracker <https://bugs.python.org/issue36582> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue11698] Improve repr for structseq objects to show named, but unindexed fields
MICHAEL BLAHAY added the comment: I have been advised to avoid enhancements like this one, so I am setting this back down. Also, this should be relabeled as easy(c). -- ___ Python tracker <https://bugs.python.org/issue11698> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue27639] UserList.__getitem__ doesn't account for slices
Michael Blahay added the comment: Here is a test that more explicitly shows the problem. >>> from collections import UserList >>> UserList([0,1,2,3,4,5])[0:2].__class__ >>> It can clearly be seen here that the return type of the slicing operator is list when it should, in this case, be UserList (or whatever class one is using that is derived from UserList). -- nosy: +mblahay ___ Python tracker <https://bugs.python.org/issue27639> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue27639] UserList.__getitem__ doesn't account for slices
Michael Blahay added the comment: The root cause of this issue seems to be the failure to implement type usage in __getitem__ when the deprecated __getslice__ was removed. This is why slicing worked correctly in 2.7, but not the 3.x versions. In 3.8, the __getitem__ method is used to create the slice, but here we can see that all it does is pass the task to data, which is of type list and then fails to convert the result to the correct type. def __getitem__(self, i): return self.data[i] Using other methods as examples, the fix should look like this: def __getitem__(self, i): return self.__class__(self.data[i]) -- ___ Python tracker <https://bugs.python.org/issue27639> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue27639] UserList.__getitem__ doesn't account for slices
Michael Blahay added the comment: It is also worth noting that the definition of UserList moved from Lib/UserList.py in 2.7 to Lib/collections/__init__.py in 3.x -- ___ Python tracker <https://bugs.python.org/issue27639> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue27639] UserList.__getitem__ doesn't account for slices
Michael Blahay added the comment: Results from a quick unit test on the proposed changes were positive: >>> from collections import UserList >>> UserList([0,1,2,3,4,5])[0:2].__class__ If you compare this result with the one a couple comments above, you can see that the result is no longer a list, but rather of type UserList. -- ___ Python tracker <https://bugs.python.org/issue27639> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue27639] UserList.__getitem__ doesn't account for slices
Michael Blahay added the comment: Thank you for bringing up that PR. My team will review and try to find out why it was closed without a merge. -- ___ Python tracker <https://bugs.python.org/issue27639> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue27639] UserList.__getitem__ doesn't account for slices
Michael Blahay added the comment: Please note that I am working with Erick Cervantes at PyCon2019 on this issue. -- ___ Python tracker <https://bugs.python.org/issue27639> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue27639] UserList.__getitem__ doesn't account for slices
Michael Blahay added the comment: Let it be known that the author of PR 4981 is known as vaultah. He/she personally closed the pull request this morning stating a lack of need to be recognized for the work. Per his/her instructions I am reviewing the changes and incorporating in our solution as needed. Thank you vaultah! -- ___ Python tracker <https://bugs.python.org/issue27639> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue35495] argparse does not honor default argument for nargs=argparse.REMAINDER argument
Michael Blahay added the comment:
Ryan, what are the exact steps to reproduce the problem? This is what I get
when I run the code you included:
>>> import argparse
>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('things', nargs=argparse.REMAINDER, default=['nothing'])
_StoreAction(option_strings=[], dest='things', nargs='...', const=None,
default=['nothing'], type=None, choices=None, help=None, metavar=None)
>>> parser.parse_args([])
Namespace(things=[])
>>> Namespace(things=[])
Traceback (most recent call last):
File "", line 1, in
NameError: name 'Namespace' is not defined
--
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[issue27639] UserList.__getitem__ doesn't account for slices
Change by Michael Blahay : -- pull_requests: +13114 ___ Python tracker <https://bugs.python.org/issue27639> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue27639] UserList.__getitem__ doesn't account for slices
Michael Blahay added the comment: PR 13150, the recreation of PR 4981, was noticed just after I created PR 13169. It was decided to continue forward with PR 13169 since PR 13150 contained changes that were out of scope for BPO-27639 for which it was suspected might have been the cause of the non-merging of PR 4981. Thank for identifying Dmitry; I did my best to give credit where credit was due. -- ___ Python tracker <https://bugs.python.org/issue27639> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue35495] argparse does not honor default argument for nargs=argparse.REMAINDER argument
Michael Blahay added the comment: Okay, so the expected output after running parse.parse_args([]) is Namespace(['nothing']) -- ___ Python tracker <https://bugs.python.org/issue35495> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue35495] argparse does not honor default argument for nargs=argparse.REMAINDER argument
Michael Blahay added the comment: Ryan, I have reviewed the documentation at https://docs.python.org/3/library/argparse.html#nargs and must admit that there is not a definitive answer that I can see regarding the defined behavior should there be no command line arguments that are in fact remaining. One could certainly argue that the empty list is the expression of the fact that no remaining arguments could be found. One can also argue that when seeking the remaining arguments, a list that may be zero to many elements in size, that by definition there cannot be a default. Can you cite any documentation that would support your claim? -- ___ Python tracker <https://bugs.python.org/issue35495> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue27639] UserList.__getitem__ doesn't account for slices
Michael Blahay added the comment: For those that are wondering what is going on with PR 13181 and PR 13203, those are both for back porting the change to 3.7. The auto generated PR 13181 failed for an unknown reason and then the bot deleted the branch so the PR could not be taken any further. PR 13203 is a manual attempt at the backport which is moving along much for successfully. -- ___ Python tracker <https://bugs.python.org/issue27639> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue35495] argparse does not honor default argument for nargs=argparse.REMAINDER argument
Michael Blahay added the comment:
For the purpose of facilitating continuing conversation, here are two tests
that contrast the use of * versus REMAINDER
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('foo', nargs=1,default=['none'])
parser.add_argument('bar', nargs=argparse.REMAINDER,default=['nothing'])
parser.add_argument('baz', nargs='*', default=['nada'])
parser.parse_args('a b c'.split())
Out[7]: Namespace(bar=['b', 'c'], baz=['nada'], foo=['a'])
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('foo', nargs=1,default=['none'])
parser.add_argument('baz', nargs='*', default=['nada'])
parser.add_argument('bar', nargs=argparse.REMAINDER,default=['nothing'])
parser.parse_args('a b c'.split())
Out[8]: Namespace(bar=[], baz=['b', 'c'], foo=['a'])
You can see that * and REMAINDER do differ in functionality when they are the
last defined argument.
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[issue35495] argparse does not honor default argument for nargs=argparse.REMAINDER argument
Michael Blahay added the comment:
Here is another take on the issue, this time illustrated through the lens of
optional arguments.
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('--foo', nargs=1,default=['none'])
parser.add_argument('--baz', nargs='*', default=['nada'])
parser.add_argument('--bar', nargs=argparse.REMAINDER,default=['nothing'])
parser.parse_args('--foo a --bar b --baz c'.split())
Out[9]: Namespace(bar=['b', '--baz', 'c'], baz=['nada'], foo=['a'])
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('--foo', nargs=1,default=['none'])
parser.add_argument('--baz', nargs='*', default=['nada'])
parser.add_argument('--bar', nargs=argparse.REMAINDER,default=['nothing'])
parser.parse_args('--foo a --baz b --bar c'.split())
Out[10]: Namespace(bar=['c'], baz=['b'], foo=['a'])
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('--foo', nargs=1,default=['none'])
parser.add_argument('--baz', nargs='*', default=['nada'])
parser.add_argument('--bar', nargs=argparse.REMAINDER,default=['nothing'])
parser.parse_args([])
Out[11]: Namespace(bar=['nothing'], baz=['nada'], foo=['none'])
It is important to note that when an optional argument is not present then the
default is always used, including for one using nargs=argparse.REMAINDER. In
all three tests, bar is the argument using REMAIDER. In the first test, one can
see that when bar isn't the last argument then anything else, including other
arguments, are swept up as being arguments of bar. This greedy behavior for
REMAINDER is something that * does not share (test 2).
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[issue35495] argparse does not honor default argument for nargs=argparse.REMAINDER argument
Michael Blahay added the comment:
With the optional arguments, the determination about whether to use the default
value is made based on whether the flag is present or not. When positional
arguments are involved, the need for the defaults seems to in part be
determined based on whether the argument exists. The fact that * and REMAINDER
are zero-to-many in nature add some ambiguity into the situation. For the *, it
seems that the positional argument only exists if there is at least one actual
argument value that it can consume.
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('foo', nargs=1,default=['none'])
#parser.add_argument('bar', nargs=argparse.REMAINDER,default=['nothing'])
parser.add_argument('baz', nargs='*', default=['nada'])
parser.parse_args('a b'.split())
Out[25]: Namespace(baz=['b'], foo=['a'])
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('foo', nargs=1,default=['none'])
#parser.add_argument('bar', nargs=argparse.REMAINDER,default=['nothing'])
parser.add_argument('baz', nargs='*', default=['nada'])
parser.parse_args('a'.split())
Out[26]: Namespace(baz=['nada'], foo=['a'])
Mean while, the REMAINDER option makes the argument act as if it exists
regardless of whether an actual argument value exists.
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('foo', nargs=1,default=['none'])
parser.add_argument('bar', nargs=argparse.REMAINDER,default=['nothing'])
#parser.add_argument('baz', nargs='*', default=['nada'])
parser.parse_args('a b'.split())
Out[27]: Namespace(bar=['b'], foo=['a'])
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('foo', nargs=1,default=['none'])
parser.add_argument('bar', nargs=argparse.REMAINDER,default=['nothing'])
#parser.add_argument('baz', nargs='*', default=['nada'])
parser.parse_args('a'.split())
Out[28]: Namespace(bar=[], foo=['a'])
To conclude, * and REMAINDER perform similar, but different, roles when used
with positional arguments. With edge cases like the ones laid out above, it can
be hard to conceptualize what the exact behavior should be. I will recommend
that the documentation be updated to convey the following message: "When used
with positional arguments, REMAINDER will never use the designated default
value list. It will instead return an empty list if there are no values for the
argument to consume. If the use of default values is desired, then * must be
used."
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[issue35495] argparse does not honor default argument for nargs=argparse.REMAINDER argument
Michael Blahay added the comment: Much detail has been provided regarding why the default is ignored when user the REMAINDER option. The desire to add an exception has not. Is there anyone that can provide guidance on whether the combination of: 1. Positional Argument 2. nargs=REMAINDER 3. default=something should raise an exception upon execution of the add_argument method? -- ___ Python tracker <https://bugs.python.org/issue35495> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue27639] UserList.__getitem__ doesn't account for slices
Michael Blahay added the comment: PR 13203 has finally made it through all checks successfully and is now awaiting merging. Please someone pick it up and merge it. Thank you -- ___ Python tracker <https://bugs.python.org/issue27639> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue35495] argparse does not honor default argument for nargs=argparse.REMAINDER argument
Michael Blahay added the comment: Ryan, What say you? Will you be satisfied with the addition of a note in the documentation? -- ___ Python tracker <https://bugs.python.org/issue35495> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue32509] doctest syntax ambiguity between continuation line and ellipsis
Michael Blahay added the comment: At the end of msg309603 it was stated that this issue is being changed to an enhancement. Later on, Tim Peters changed it Type back to behavior, but didn't provide any detail about why. Should this issue still be considered an enhancement? -- nosy: +mblahay ___ Python tracker <https://bugs.python.org/issue32509> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue27639] UserList.__getitem__ doesn't account for slices
Michael Blahay added the comment: PR 13203 is still waiting for merge -- ___ Python tracker <https://bugs.python.org/issue27639> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue27639] UserList.__getitem__ doesn't account for slices
Michael Blahay added the comment: PR 13203 is still waiting for merge -- ___ Python tracker <https://bugs.python.org/issue27639> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue27639] UserList.__getitem__ doesn't account for slices
Michael Blahay added the comment: Thank you Mark. Everything for this one is complete. The issue may be closed. -- ___ Python tracker <https://bugs.python.org/issue27639> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue35495] argparse does not honor default argument for nargs=argparse.REMAINDER argument
Michael Blahay added the comment: Ryan, last chance, do you have any feedback? -- ___ Python tracker <https://bugs.python.org/issue35495> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue36913] Missing documentation for decorators
Michael Blahay added the comment: The PEP is not the first place I go looking for information on Python topics, just my two cents. -- nosy: +mblahay ___ Python tracker <https://bugs.python.org/issue36913> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue17250] argparse: Issue 15906 patch; positional with nargs='*' and string default
Michael Blahay added the comment: Also see https://bugs.python.org/issue35495 -- nosy: +mblahay ___ Python tracker <https://bugs.python.org/issue17250> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue35495] argparse does not honor default argument for nargs=argparse.REMAINDER argument
Michael Blahay added the comment: Need some help searching github to determine the blast radius of the proposed changes. How does one look for instances of argparse.REMAINDER that are used with a default value? -- ___ Python tracker <https://bugs.python.org/issue35495> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue35495] argparse does not honor default argument for nargs=argparse.REMAINDER argument
Michael Blahay added the comment: Ryan, I like option A as well, but it is a breaking change. Unlike in a compiled language where we could output a warning, making the proposed change could bring some software to a grinding halt. For now I'm going to make the documentation change and this issue can stay open for if there is a major version change that would allow such a breaking change. -- versions: +Python 3.9 -Python 2.7, Python 3.6, Python 3.7, Python 3.8 ___ Python tracker <https://bugs.python.org/issue35495> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
