69 lines
1.4 KiB
Python
69 lines
1.4 KiB
Python
def count(start=0, step=1):
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while True:
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yield start
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start += step
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def cycle(p):
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try:
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len(p)
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except TypeError:
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# len() is not defined for this type. Assume it is
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# a finite iterable so we must cache the elements.
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cache = []
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for i in p:
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yield i
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cache.append(i)
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p = cache
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while p:
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yield from p
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def repeat(el, n=None):
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if n is None:
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while True:
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yield el
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else:
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for i in range(n):
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yield el
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def chain(*p):
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for i in p:
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yield from i
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def islice(p, start, stop=(), step=1):
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if stop == ():
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stop = start
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start = 0
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# TODO: optimizing or breaking semantics?
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if start >= stop:
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return
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it = iter(p)
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for i in range(start):
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next(it)
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while True:
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yield next(it)
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for i in range(step - 1):
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next(it)
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start += step
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if start >= stop:
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return
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def tee(iterable, n=2):
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return [iter(iterable)] * n
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def starmap(function, iterable):
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for args in iterable:
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yield function(*args)
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def accumulate(iterable, func=lambda x, y: x + y):
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it = iter(iterable)
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try:
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acc = next(it)
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except StopIteration:
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return
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yield acc
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for element in it:
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acc = func(acc, element)
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yield acc
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