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1
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# Iterators and iterables
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2
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3
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def is_iterable(value): return getattr(value, '__iter__', False)
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4
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5
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# Sentinel to use in iter() if function return value should be ignored
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6
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iter_end = object()
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7
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8
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def func_iter(func):
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9
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'''Used to iterate a generating function which raises StopIteration instead
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10
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of returning a sentinel value'''
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11
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return iter(func, iter_end)
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12
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13
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def consume_iter(iter_):
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14
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for elem in iter_: pass
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15
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16
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def flatten(outer_iter):
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17
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if is_iterable(outer_iter):
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18
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for iter_ in outer_iter:
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19
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if is_iterable(iter_):
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20
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for el in iter_: yield el
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21
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else: yield iter_
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22
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else: yield outer_iter
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23
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24
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def flatten_n(outer_iter, depth=2):
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25
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if depth < 2: return outer_iter
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26
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elif depth == 2: return flatten(outer_iter)
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27
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else: return flatten(flatten_n(outer_iter, depth-1))
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