Question

class Vector(object):
    def __init__(self,coordinates):
        try:
            if not coordinates:
                raise ValueError
            self.coordinates=coordinates
            self.dimension=len(coordinates)

        except ValueError:
            raise ValueError('The coordinates must be non empty')

        except TypeError:
            raise TypeError('The coordinates must be iterable')

    def __str__(self):
        return 'Vector: {}'.format(self.coordinates)

    def magnitude(self):
        mag = [(sum(x**2 for x in self.coordinates))**0.5]
        return Vector(mag)

    def normalize(self):
        mag= self.magnitude()
        normal= [((1/mag)*x for x in self.coordinates)]
        return Vector(normal)

vector_m=Vector([5.581,-2.136])
print vector_m.normalize()

vector_m=Vector([-0.221,7.437])
print vector_m.magnitude()

Answer 1

此

normal= [((1/mag)*x for x in self.coordinates)]

创建包含生成器的1元素列表。表达式

((1/mag)*x for x in self.coordinates)

是generator expression。你想要的是：

normal= [(1/mag)*x for x in self.coordinates]

我得到一个结果＆＃34; [<generator object =“”<genexpr =“”>在0x00000000029FC870＆gt;]＆＃34;？我的代码在这里出了什么问题

1 个答案: