python - 根据可能取多个值的参数有效地定义变量

Question

我有这个函数，它根据参数 orientation 的值定义和返回变量 a 和 b。

        def myfunc(orientation, l, w):


            if orientation == 1:
                a = -w
                b = l
            elif orientation == 2:
                a = -l
                b = w
            elif orientation == 3:
                a = -w
                b = -l
            elif orientation == 4:
                a = -l
                b = -w
            elif orientation == 5:
                a = w
                b = l
            elif orientation == 6:
                a = l
                b = w
            elif orientation == 7:
                a = w
                b = -l
            elif orientation == 8:
                a = l
                b = -w

            return a, b

我的问题是:是否有更紧凑和/或更有效的方法来做同样的事情？如果有更好的方法，是什么？

Answer 1

首先，循环是不必要的；只会返回在最后一次迭代中分配的值。一旦你摆脱了这些，就很容易看到模式:

def myfunc(orientation, l, w):

    a, b = (w, l) if orientation % 2 else (l, w)

    if orientation <= 4:
        a = -a
    if orientation in (3, 4, 7, 8):
        b = -b

    return a, b