24 lines
675 B
Python
24 lines
675 B
Python
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from setuptools.extern.more_itertools import consume # noqa: F401
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# copied from jaraco.itertools 6.1
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def ensure_unique(iterable, key=lambda x: x):
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"""
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Wrap an iterable to raise a ValueError if non-unique values are encountered.
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>>> list(ensure_unique('abc'))
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['a', 'b', 'c']
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>>> consume(ensure_unique('abca'))
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Traceback (most recent call last):
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...
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ValueError: Duplicate element 'a' encountered.
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"""
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seen = set()
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seen_add = seen.add
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for element in iterable:
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k = key(element)
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if k in seen:
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raise ValueError(f"Duplicate element {element!r} encountered.")
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seen_add(k)
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yield element
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