[issue21771] name of 2nd parameter to itertools.groupby()
New submission from Uwe Kleine-König: The name of the 2nd parameter to itertools.groupby() is documented inconsitently. Sometimes it's key, sometimes keyfunc. The code actually uses key, so I adapted all occurences I found to key. from itertools import groupby groupby.__doc__ 'groupby(iterable[, keyfunc]) - create an iterator which returns\n(key, sub-iterator) grouped by each value of key(value).\n' groupby([], keyfunc=lambda x: x) Traceback (most recent call last): File stdin, line 1, in module TypeError: 'keyfunc' is an invalid keyword argument for this function groupby([], key=lambda x: x) itertools.groupby object at 0x7fee025d2048 -- assignee: docs@python components: Documentation files: groupby-keyfunc.patch keywords: patch messages: 220639 nosy: docs@python, ukl priority: normal severity: normal status: open title: name of 2nd parameter to itertools.groupby() type: enhancement versions: Python 2.7, Python 3.3, Python 3.4, Python 3.5 Added file: http://bugs.python.org/file35645/groupby-keyfunc.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21771 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21771] name of 2nd parameter to itertools.groupby()
Changes by Ned Deily n...@acm.org: -- nosy: +rhettinger ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21771 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21771] name of 2nd parameter to itertools.groupby()
Raymond Hettinger added the comment: There is a bit an inconsistency but it is more helpful than harmful most of the time. The glossary defines a key-function which is used in a number of places such such as sorted(), min(), nsmallest() and others. In all those cases, the parameter for the key-function is *key*. It might feel more consistent to call it key everywhere, but that leaves out the explanation that *key* represents a key-function. The other issue is that groupby() returns a (key, sub-iterator) pair where key is the result of key-function, not the key itself. What we have now is imperfect but it does a reasonably good job helping people understand what the function does. IMO, changing it to be key would make the docs less intelligible. Thank you for the patch, but I'm going to pass on it. -- resolution: - rejected status: open - closed ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21771 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
