2019-06-28 16:33:59 +02:00
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def validate_isbn(isbn):
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_sum = 0
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if len(isbn) == 10:
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for i, digit in enumerate(isbn):
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2021-07-10 12:11:58 +02:00
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if digit == "X":
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2019-06-28 16:33:59 +02:00
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digit = 10
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else:
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digit = int(digit)
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_sum += digit * (i + 1)
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return _sum % 11 == 0
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elif len(isbn) == 13:
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for i, digit in enumerate(isbn):
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weight = 3 if i % 2 == 1 else 1
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digit = int(digit)
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_sum += digit * weight
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return _sum % 10 == 0
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return False
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