Permutations Python code equivalent in comment was invalid for Python 3 (GH-16927)
diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
index e60ad5b..3d39fa2 100644
--- a/Modules/itertoolsmodule.c
+++ b/Modules/itertoolsmodule.c
@@ -3076,12 +3076,15 @@
/* permutations object ********************************************************
def permutations(iterable, r=None):
- 'permutations(range(3), 2) --> (0,1) (0,2) (1,0) (1,2) (2,0) (2,1)'
+ # permutations('ABCD', 2) --> AB AC AD BA BC BD CA CB CD DA DB DC
+ # permutations(range(3)) --> 012 021 102 120 201 210
pool = tuple(iterable)
n = len(pool)
r = n if r is None else r
- indices = range(n)
- cycles = range(n-r+1, n+1)[::-1]
+ if r > n:
+ return
+ indices = list(range(n))
+ cycles = list(range(n, n-r, -1))
yield tuple(pool[i] for i in indices[:r])
while n:
for i in reversed(range(r)):