https://github.com/python/cpython/commit/a85e512699512893f34329b9ddab5ec5ad8... commit: a85e512699512893f34329b9ddab5ec5ad8a19bb branch: 3.12 author: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> committer: rhettinger <rhettinger@users.noreply.github.com> date: 2024-02-28T17:11:46-06:00 summary: [3.12] Improve all_equal() recipe (gh-116081) (gh-116083) files: M Doc/library/itertools.rst diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst index 8ae7a304ff12f4..82d24a752a4aaa 100644 --- a/Doc/library/itertools.rst +++ b/Doc/library/itertools.rst @@ -855,10 +855,9 @@ which incur interpreter overhead. "Given a predicate that returns True or False, count the True results." return sum(map(pred, iterable)) - def all_equal(iterable): + def all_equal(iterable, key=None): "Returns True if all the elements are equal to each other." - g = groupby(iterable) - return next(g, True) and not next(g, False) + return len(take(2, groupby(iterable, key))) <= 1 def first_true(iterable, default=False, pred=None): """Returns the first true value in the iterable. @@ -1217,6 +1216,8 @@ The following recipes have a more mathematical flavor: >>> [all_equal(s) for s in ('', 'A', 'AAAA', 'AAAB', 'AAABA')] [True, True, True, False, False] + >>> [all_equal(s, key=str.casefold) for s in ('', 'A', 'AaAa', 'AAAB', 'AAABA')] + [True, True, True, False, False] >>> quantify(range(99), lambda x: x%2==0) 50