Replace the window() example with pairwise() which demonstrates tee().

1 files changed, 10 insertions, 13 deletions

diff --git a/Lib/test/test_itertools.py b/Lib/test/test_itertools.py
index e12aa41..07219a9 100644
--- a/Lib/test/test_itertools.py
+++ b/Lib/test/test_itertools.py
@@ -623,16 +623,10 @@ Samuele
 ...     else:
 ...         return starmap(func, repeat(args, times))
 
->>> def window(seq, n=2):
-...     "Returns a sliding window (of width n) over data from the iterable"
-...     "   s -> (s0,s1,...s[n-1]), (s1,s2,...,sn), ...                   "
-...     it = iter(seq)
-...     result = tuple(islice(it, n))
-...     if len(result) == n:
-...         yield result
-...     for elem in it:
-...         result = result[1:] + (elem,)
-...         yield result
+>>> def pairwise(iterable):
+...     "s -> (s0,s1), (s1,s2), (s2, s3), ..."
+...     a, b = tee(iterable)
+...     return izip(a, islice(b, 1, None))
 
 This is not part of the examples but it tests to make sure the definitions
 perform as purported.
@@ -681,10 +675,13 @@ False
 >>> take(5, imap(int, repeatfunc(random.random)))
 [0, 0, 0, 0, 0]
 
->>> list(window('abc'))
-[('a', 'b'), ('b', 'c')]
+>>> list(pairwise('abcd'))
+[('a', 'b'), ('b', 'c'), ('c', 'd')]
 
->>> list(window('abc',5))
+>>> list(pairwise([]))
+[]
+
+>>> list(pairwise('a'))
 []
 
 >>> list(islice(padnone('abc'), 0, 6))