如何在numpy数组的元素之间插入零? [英] How to insert zeros between elements in a numpy array?

问题描述

我有一个nd数组，例如:

I have an nd array, for example this:

x = np.array([[1,2,3],[4,5,6]])

我想将最后一个尺寸的大小加倍，并在元素之间插入零以填充空间.结果应如下所示:

I would like to double the size of the last dimension, and insert zeroes between the elements to fill the space. The result should look like this:

[[1,0,2,0,3,0],[4,0,5,0,6,0]]

我试图使用expand_dims和pad解决它.但是pad函数不仅在最后一个维度中的每个值之后插入零.结果的形状为(3, 4, 2)，但应为(2,3,2)

I tried to solve it using expand_dims and pad. But the pad function inserts zeroes not just after each value in the last dimension. The shape of it's result is (3, 4, 2), but it should be (2,3,2)

y = np.expand_dims(x,-1)
z = np.pad(y, (0,1), 'constant', constant_values=0)
res = np.reshape(z,[-1,2*3]

我的代码的结果:

array([[1, 0, 2, 0, 3, 0],
       [0, 0, 4, 0, 5, 0],
       [6, 0, 0, 0, 0, 0],
       [0, 0, 0, 0, 0, 0]])

使用pad如何在每个元素之后的最后一个维度中插入零?还是有解决这个问题的更好方法?

How is it possible with pad to insert zeroes in the last dimension after each element? Or is there any better way to solve the problem?

推荐答案

简单地初始化输出数组并使用slicing-

Simply initialize output array and assign with slicing -

m,n = x.shape
out = np.zeros((m,2*n),dtype=x.dtype)
out[:,::2] = x

或者堆叠-

np.dstack((x,np.zeros_like(x))).reshape(x.shape[0],-1)

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