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| author | Raymond Hettinger <rhettinger@users.noreply.github.com> | 2020-12-30 20:51:19 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2020-12-30 20:51:19 (GMT) |
| commit | f421bfce80730cb0ff5cbe14727ac30cf0462eed (patch) | |
| tree | 5c6fd1941e97fd60f8b855bd27851e002b738103 | |
| parent | 4ac923f2756f835f512339ee181348cc535ab07f (diff) | |
| download | cpython-f421bfce80730cb0ff5cbe14727ac30cf0462eed.zip cpython-f421bfce80730cb0ff5cbe14727ac30cf0462eed.tar.gz cpython-f421bfce80730cb0ff5cbe14727ac30cf0462eed.tar.bz2 | |
Minor improvements to the convolve() recipe (GH-24012)
* Minor improvement to speed and space efficiency for the convolve() recipe
* Don't require convolve's kernel to be a sequence.
| -rw-r--r-- | Doc/library/itertools.rst | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst index 03416a0..fd77f99 100644 --- a/Doc/library/itertools.rst +++ b/Doc/library/itertools.rst @@ -791,9 +791,9 @@ 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)) |