mirror of https://github.com/python/cpython
Add more itertool recipes (GH-28165)
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@ -492,6 +492,8 @@ loops that truncate the stream.
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next(b, None)
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return zip(a, b)
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.. versionadded:: 3.10
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.. function:: permutations(iterable, r=None)
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@ -812,11 +814,27 @@ which incur interpreter overhead.
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return starmap(func, repeat(args, times))
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def grouper(iterable, n, fillvalue=None):
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"Collect data into fixed-length chunks or blocks"
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# grouper('ABCDEFG', 3, 'x') --> ABC DEF Gxx"
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"Collect data into non-overlapping fixed-length chunks or blocks"
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# grouper('ABCDEFG', 3, 'x') --> ABC DEF Gxx
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args = [iter(iterable)] * n
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return zip_longest(*args, fillvalue=fillvalue)
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def triplewise(iterable):
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"Return overlapping triplets from an iterable"
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# pairwise('ABCDEFG') -> ABC BCD CDE DEF EFG
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for (a, _), (b, c) in pairwise(pairwise(iterable)):
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yield a, b, c
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def sliding_window(iterable, n):
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# sliding_window('ABCDEFG', 4) -> ABCD BCDE CDEF DEFG
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it = iter(iterable)
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window = deque(islice(it, n), maxlen=n)
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if len(window) == n:
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yield tuple(window)
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for x in it:
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window.append(x)
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yield tuple(window)
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def roundrobin(*iterables):
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"roundrobin('ABC', 'D', 'EF') --> A D E B F C"
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# Recipe credited to George Sakkis
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@ -2394,6 +2394,23 @@ Samuele
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... else:
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... return starmap(func, repeat(args, times))
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>>> def triplewise(iterable):
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... "Return overlapping triplets from an iterable"
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... # pairwise('ABCDEFG') -> ABC BCD CDE DEF EFG
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... for (a, _), (b, c) in pairwise(pairwise(iterable)):
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... yield a, b, c
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>>> import collections
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>>> def sliding_window(iterable, n):
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... # sliding_window('ABCDEFG', 4) -> ABCD BCDE CDEF DEFG
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... it = iter(iterable)
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... window = collections.deque(islice(it, n), maxlen=n)
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... if len(window) == n:
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... yield tuple(window)
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... for x in it:
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... window.append(x)
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... yield tuple(window)
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>>> def grouper(n, iterable, fillvalue=None):
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... "grouper(3, 'ABCDEFG', 'x') --> ABC DEF Gxx"
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... args = [iter(iterable)] * n
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@ -2570,6 +2587,12 @@ True
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>>> list(grouper(3, 'abcdefg', 'x'))
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[('a', 'b', 'c'), ('d', 'e', 'f'), ('g', 'x', 'x')]
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>>> list(triplewise('ABCDEFG'))
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[('A', 'B', 'C'), ('B', 'C', 'D'), ('C', 'D', 'E'), ('D', 'E', 'F'), ('E', 'F', 'G')]
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>>> list(sliding_window('ABCDEFG', 4))
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[('A', 'B', 'C', 'D'), ('B', 'C', 'D', 'E'), ('C', 'D', 'E', 'F'), ('D', 'E', 'F', 'G')]
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>>> list(roundrobin('abc', 'd', 'ef'))
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['a', 'd', 'e', 'b', 'f', 'c']
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