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Minor clarity improvement for the iter_index() recipe. Also add value subsequence tests. (gh-116696)
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@ -902,18 +902,19 @@ which incur interpreter overhead.
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# iter_index('AABCADEAF', 'A') --> 0 1 4 7
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seq_index = getattr(iterable, 'index', None)
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if seq_index is None:
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# Slow path for general iterables
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# Path for general iterables
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it = islice(iterable, start, stop)
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for i, element in enumerate(it, start):
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if element is value or element == value:
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yield i
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else:
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# Fast path for sequences
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# Path for sequences with an index() method
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stop = len(iterable) if stop is None else stop
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i = start - 1
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i = start
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try:
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while True:
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yield (i := seq_index(value, i+1, stop))
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yield (i := seq_index(value, i, stop))
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i += 1
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except ValueError:
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pass
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@ -1412,6 +1413,22 @@ The following recipes have a more mathematical flavor:
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>>> ''.join(input_iterator)
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'DEAF'
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>>> # Verify that the target value can be a sequence.
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>>> seq = [[10, 20], [30, 40], 30, 40, [30, 40], 50]
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>>> target = [30, 40]
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>>> list(iter_index(seq, target))
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[1, 4]
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>>> # Verify faithfulness to type specific index() method behaviors.
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>>> # For example, bytes and str perform subsequence searches
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>>> # that do not match the general behavior specified
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>>> # in collections.abc.Sequence.index().
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>>> seq = 'abracadabra'
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>>> target = 'ab'
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>>> list(iter_index(seq, target))
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[0, 7]
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>>> list(sieve(30))
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[2, 3, 5, 7, 11, 13, 17, 19, 23, 29]
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>>> small_primes = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97]
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