17 lines
465 B
Python
17 lines
465 B
Python
"""util functions for collections_extended."""
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def hash_iterable(it):
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"""Perform a O(1) memory hash of an iterable of arbitrary length.
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hash(tuple(it)) creates a temporary tuple containing all values from it
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which could be a problem if it is large.
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See discussion at:
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https://groups.google.com/forum/#!msg/python-ideas/XcuC01a8SYs/e-doB9TbDwAJ
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"""
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hash_value = hash(type(it))
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for value in it:
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hash_value = hash((hash_value, value))
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return hash_value
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