32 lines
920 B
Python
32 lines
920 B
Python
"""
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Providing iterator functions that are not in all version of Python we support.
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Where possible, we try to use the system-native version and only fall back to
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these implementations if necessary.
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"""
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import itertools
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def compat_tee(iterable):
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"""Return two independent iterators from a single iterable.
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Based on http://www.python.org/doc/2.3.5/lib/itertools-example.html
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"""
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# Note: Using a dictionary and a list as the default arguments here is
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# deliberate and safe in this instance.
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def gen(next, data={}, cnt=[0]):
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dpop = data.pop
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for i in itertools.count():
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if i == cnt[0]:
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item = data[i] = next()
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cnt[0] += 1
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else:
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item = dpop(i)
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yield item
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next = iter(iterable).next
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return gen(next), gen(next)
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if hasattr(itertools, 'tee'):
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tee = itertools.tee
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else:
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tee = compat_tee
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