python - numpy Zeros 如何实现参数形状？

Question

我想要实现类似的函数，并且想要接受传递给 numpy.ones 的数组或数字。

具体来说，我想这样做:

def halfs(shape):
    shape = numpy.concatenate([2], shape)
    return 0.5 * numpy.ones(shape)

输入输出对示例:

# default
In [5]: beta_jeffreys()
Out[5]: array([-0.5, -0.5])

# scalar
In [5]: beta_jeffreys(3)
Out[3]: 
array([[-0.5, -0.5, -0.5],
       [-0.5, -0.5, -0.5]])

# vector (1)
In [3]: beta_jeffreys((3,))
Out[3]: 
array([[-0.5, -0.5, -0.5],
       [-0.5, -0.5, -0.5]])

# vector (2)
In [7]: beta_jeffreys((2,3))
Out[7]: 
array([[[-0.5, -0.5, -0.5],
        [-0.5, -0.5, -0.5]],

       [[-0.5, -0.5, -0.5],
        [-0.5, -0.5, -0.5]]])

Answer 1

def halfs(shape=()):
    if isinstance(shape, tuple):
        return 0.5 * numpy.ones((2,) + shape)
    else:
        return 0.5 * numpy.ones((2, shape))



a = numpy.arange(5)
# array([0, 1, 2, 3, 4])


halfs(a.shape)
#array([[ 0.5,  0.5,  0.5,  0.5,  0.5],
#       [ 0.5,  0.5,  0.5,  0.5,  0.5]])

halfs(3)
#array([[ 0.5,  0.5,  0.5],
#       [ 0.5,  0.5,  0.5]])