Docs: Clarify the before_and_after() example (GH-28458) (#28464)
(cherry picked from commit fcbf9b176b1190301c760a921601c6488ef8b070)
Co-authored-by: Raymond Hettinger <rhettinger@users.noreply.github.com>
Co-authored-by: Raymond Hettinger <rhettinger@users.noreply.github.com>
diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst
index ac6b354..61d8b86 100644
--- a/Doc/library/itertools.rst
+++ b/Doc/library/itertools.rst
@@ -859,10 +859,11 @@
""" Variant of takewhile() that allows complete
access to the remainder of the iterator.
- >>> all_upper, remainder = before_and_after(str.isupper, 'ABCdEfGhI')
- >>> str.join('', all_upper)
+ >>> it = iter('ABCdEfGhI')
+ >>> all_upper, remainder = before_and_after(str.isupper, it)
+ >>> ''.join(all_upper)
'ABC'
- >>> str.join('', remainder)
+ >>> ''.join(remainder) # takewhile() would lose the 'd'
'dEfGhI'
Note that the first iterator must be fully
diff --git a/Lib/test/test_itertools.py b/Lib/test/test_itertools.py
index aa81076..a12f6f0 100644
--- a/Lib/test/test_itertools.py
+++ b/Lib/test/test_itertools.py
@@ -2605,10 +2605,11 @@ def test_permutations_sizeof(self):
>>> list(odds)
[1, 3, 5, 7, 9]
->>> all_upper, remainder = before_and_after(str.isupper, 'ABCdEfGhI')
->>> str.join('', all_upper)
+>>> it = iter('ABCdEfGhI')
+>>> all_upper, remainder = before_and_after(str.isupper, it)
+>>> ''.join(all_upper)
'ABC'
->>> str.join('', remainder)
+>>> ''.join(remainder)
'dEfGhI'
>>> list(powerset([1,2,3]))