[Python-checkins] [3.9] Minor improvements to the convolve() recipe (GH-24520)

[pablogsal]

https://github.com/python/cpython/commit/9cc70bc22040932d257f6ba04bab812134110a74
commit: 9cc70bc22040932d257f6ba04bab812134110a74
branch: 3.9
author: Pablo Galindo <Pablogsal at gmail.com>
committer: pablogsal <Pablogsal at gmail.com>
date: 2021-02-15T23:02:41Z
summary:

[3.9] Minor improvements to the convolve() recipe (GH-24520)

files:
M Doc/library/itertools.rst
M Doc/tools/susp-ignored.csv

diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst
index ff5b60d70ff4e..6da55f8a3f49c 100644
--- a/Doc/library/itertools.rst
+++ b/Doc/library/itertools.rst
@@ -774,9 +774,9 @@ which incur interpreter overhead.
        # convolve(data, [0.25, 0.25, 0.25, 0.25]) --> Moving average (blur)
        # convolve(data, [1, -1]) --> 1st finite difference (1st derivative)
        # convolve(data, [1, -2, 1]) --> 2nd finite difference (2nd derivative)
-       kernel = list(reversed(kernel))
+       kernel = tuple(kernel)[::-1]
        n = len(kernel)
-       window = collections.deque([0] * n, maxlen=n)
+       window = collections.deque([0], maxlen=n) * n
        for x in chain(signal, repeat(0, n-1)):
            window.append(x)
            yield sum(map(operator.mul, kernel, window))
diff --git a/Doc/tools/susp-ignored.csv b/Doc/tools/susp-ignored.csv
index c9777c6be9334..9f0c42a9bb5ab 100644
--- a/Doc/tools/susp-ignored.csv
+++ b/Doc/tools/susp-ignored.csv
@@ -171,6 +171,7 @@ library/ipaddress,,:db00,2001:db00::0/ffff:ff00::
 library/ipaddress,,::,2001:db00::0/ffff:ff00::
 library/itertools,,:step,elements from seq[start:stop:step]
 library/itertools,,:stop,elements from seq[start:stop:step]
+library/itertools,,::,kernel = tuple(kernel)[::-1]
 library/logging.handlers,,:port,host:port
 library/mmap,,:i2,obj[i1:i2]
 library/multiprocessing,,`,# Add more tasks using `put()`