Tweak recipes and tests
diff --git a/Lib/test/test_itertools.py b/Lib/test/test_itertools.py
index 3bd2255..696fdeb 100644
--- a/Lib/test/test_itertools.py
+++ b/Lib/test/test_itertools.py
@@ -410,6 +410,28 @@
self.assertEqual(len(list(product(*[range(7)]*6))), 7**6)
self.assertRaises(TypeError, product, range(6), None)
+ def product1(*args, **kwds):
+ pools = map(tuple, args) * kwds.get('repeat', 1)
+ n = len(pools)
+ if n == 0:
+ yield ()
+ return
+ if any(len(pool) == 0 for pool in pools):
+ return
+ indices = [0] * n
+ yield tuple(pool[i] for pool, i in zip(pools, indices))
+ while 1:
+ for i in reversed(range(n)): # right to left
+ if indices[i] == len(pools[i]) - 1:
+ continue
+ indices[i] += 1
+ for j in range(i+1, n):
+ indices[j] = 0
+ yield tuple(pool[i] for pool, i in zip(pools, indices))
+ break
+ else:
+ return
+
def product2(*args, **kwds):
'Pure python version used in docs'
pools = map(tuple, args) * kwds.get('repeat', 1)
@@ -425,6 +447,7 @@
args = [random.choice(argtypes) for j in range(random.randrange(5))]
expected_len = prod(map(len, args))
self.assertEqual(len(list(product(*args))), expected_len)
+ self.assertEqual(list(product(*args)), list(product1(*args)))
self.assertEqual(list(product(*args)), list(product2(*args)))
args = map(iter, args)
self.assertEqual(len(list(product(*args))), expected_len)
@@ -1213,7 +1236,7 @@
... return sum(imap(operator.mul, vec1, vec2))
>>> def flatten(listOfLists):
-... return list(chain(*listOfLists))
+... return list(chain.from_iterable(listOfLists))
>>> def repeatfunc(func, times=None, *args):
... "Repeat calls to func with specified arguments."
@@ -1226,15 +1249,15 @@
>>> def pairwise(iterable):
... "s -> (s0,s1), (s1,s2), (s2, s3), ..."
... a, b = tee(iterable)
-... try:
-... b.next()
-... except StopIteration:
-... pass
+... for elem in b:
+... break
... return izip(a, b)
->>> def grouper(n, iterable, padvalue=None):
+>>> def grouper(n, iterable, fillvalue=None):
... "grouper(3, 'abcdefg', 'x') --> ('a','b','c'), ('d','e','f'), ('g','x','x')"
-... return izip(*[chain(iterable, repeat(padvalue, n-1))]*n)
+... args = [iter(iterable)] * n
+... kwds = dict(fillvalue=fillvalue)
+... return izip_longest(*args, **kwds)
>>> def roundrobin(*iterables):
... "roundrobin('abc', 'd', 'ef') --> 'a', 'd', 'e', 'b', 'f', 'c'"