python - 两个英制长度之差

Question

我有一个程序，它采用两个英制长度(英里、码、英尺和英寸)并输出它们的和与差。我的问题是，当差异为负时，输出不正确。

def to_inches(miles, yards, feet, inches):
    return inches + (feet * 12) + (yards * 36) + (miles * 63360)


def from_inches(inches):
    miles = inches // 63360
    inches %= 63360

    yards = inches // 36
    inches %= 36

    feet = inches // 12
    inches %= 12

    return (miles, yards, feet, inches)

units1 = [int(n) for n in input().split(' ')]
units2 = [int(n) for n in input().split(' ')]

m_sum = from_inches(to_inches(*units1) + to_inches(*units2))
m_diff = from_inches(to_inches(*units1) - to_inches(*units2))

print(' '.join(str(n) for n in m_sum))
print(' '.join(str(n) for n in m_diff))

输入:

2 850 1 7
1 930 1 4

输出:

4 21 0 11
0 1680 1 3

输入:

0 1 0 0
1 0 0 0

预期输出:

1 1 0 0
-0 1759 0 0

实际输出:

1 1 0 0
-1 1 0 0

Answer 1

这是因为当涉及到负数时，Python 对模运算符 % 的处理有点奇怪。查看此答案:https://stackoverflow.com/a/3883019/436282