在numpy数组的交替行和列中插入值

Question

我需要插入任意数量的零以替换numpy数组的行和列。例如，假设我们要在所有备用列和行中插入1个零。

Input => [[ 1,2,3],
           [ 4,5,6],
           [ 7,8,9]]

output => [[ 1,0,2,0,3],
           [ 0,0,0,0,0],
           [ 4,0,5,0,6],
           [ 0,0,0,0,0],
           [ 7,0,8,0,9]] 

我知道如何通过使用循环来实现，但是我不确定这是否是最有效的方法，或者是否有可能实现矢量化。

Answer 1

一种zeros-initialization使用分步切片进行分配的方法-

def insert_zeros(a, N=1):
    # a : Input array
    # N : number of zeros to be inserted between consecutive rows and cols 
    out = np.zeros( (N+1)*np.array(a.shape)-N,dtype=a.dtype)
    out[::N+1,::N+1] = a
    return out

样品运行-

In [167]: a
Out[167]: 
array([[83, 87, 19, 24],
       [28, 24, 24, 77],
       [26, 87, 57, 37]])

In [168]: insert_zeros(a, N=1)
Out[168]: 
array([[83,  0, 87,  0, 19,  0, 24],
       [ 0,  0,  0,  0,  0,  0,  0],
       [28,  0, 24,  0, 24,  0, 77],
       [ 0,  0,  0,  0,  0,  0,  0],
       [26,  0, 87,  0, 57,  0, 37]])

In [169]: insert_zeros(a, N=2)
Out[169]: 
array([[83,  0,  0, 87,  0,  0, 19,  0,  0, 24],
       [ 0,  0,  0,  0,  0,  0,  0,  0,  0,  0],
       [ 0,  0,  0,  0,  0,  0,  0,  0,  0,  0],
       [28,  0,  0, 24,  0,  0, 24,  0,  0, 77],
       [ 0,  0,  0,  0,  0,  0,  0,  0,  0,  0],
       [ 0,  0,  0,  0,  0,  0,  0,  0,  0,  0],
       [26,  0,  0, 87,  0,  0, 57,  0,  0, 37]])