用python实验2. 设计三维向量类】设计一个三维向量类，并实现向量的加法、减法以及向量与标量的乘法 和除法运算

在Python中，我们可以创建一个名为`Vector3D`的类，来表示三维向量并实现基本的数学操作。这里是一个简单的实现：

class Vector3D:
    def __init__(self, x=0, y=0, z=0):
        self.x = x
        self.y = y
        self.z = z

    # 向量加法
    def __add__(self, other):
        if isinstance(other, Vector3D):
            return Vector3D(self.x + other.x, self.y + other.y, self.z + other.z)
        else:
            raise ValueError("Cannot add a vector to a non-vector")

    # 向量减法
    def __sub__(self, other):
        if isinstance(other, Vector3D):
            return Vector3D(self.x - other.x, self.y - other.y, self.z - other.z)
        else:
            raise ValueError("Cannot subtract a vector from a non-vector")

    # 向量与标量乘法（点积）
    def __mul__(self, scalar):
        if isinstance(scalar, (int, float)):
            return Vector3D(self.x * scalar, self.y * scalar, self.z * scalar)
        else:
            raise ValueError("Cannot multiply a vector by a non-scalar")

    # 向量与标量除法（相当于缩小向量长度）
    def __truediv__(self, scalar):
        if isinstance(scalar, (int, float)) and scalar != 0:
            magnitude = scalar
        else:
            raise ValueError("Cannot divide a vector by zero")
        return Vector3D(self.x / magnitude, self.y / magnitude, self.z / magnitude)

# 示例
v1 = Vector3D(1, 2, 3)
v2 = Vector3D(4, 5, 6)
print(f"v1: {v1}, v2: {v2}")

# 加法
result_add = v1 + v2
print(f"v1 + v2: {result_add}")

# 减法
result_sub = v1 - v2
print(f"v1 - v2: {result_sub}")

# 与标量相乘
product_scalar = v1 * 2
print(f"v1 * 2: {product_scalar}")

# 与标量相除
normalized_v1 = v1 / 5
print(f"v1 / 5 (normalized): {normalized_v1}")