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[return to "My Favorite Programming Problem to Teach: Digit Length"]
1. jepler+N3[view] [source] 2019-11-10 22:44:41
>>jstrie+(OP)
But the math.log10 solution is unfortunately "wrong" too, at least in my python3 implementation.

    import math

    def digitLengthCorrect(n):
        return len(str(n))

    def digitLengthClever2(n):
        return 1 if n == 0 else (math.floor(math.log10(n)) + 1)

    testcases = (
        [10 ** i for i in range(300)] +
        [(10 ** i) - 1 for i in range(300)]
    )

    for t in testcases:
        a = digitLengthCorrect(t)
        b = digitLengthClever2(t)
        assert a == b, (t, a, b)
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2. jstrie+v5[view] [source] 2019-11-10 23:06:05
>>jepler+N3
Interesting point, could be worth adding a note to students about the finite precision of floating point numbers in Python. Thanks for pointing this out!
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