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| -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 03416a0a7f..fd77f99a88 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)) |