如何在现有矩阵中随机添加n个零？

Question

我使用default_rng生成了这个数组：

import numpy as np
from numpy.random import default_rng
rng = default_rng(seed=10)
rng = rng.integers(1,20,(5,10))
rng

>>>array([[15, 19,  6,  4, 16, 16, 10,  3, 16, 10],
          [ 3,  3,  8, 14,  8, 16,  1,  9, 10, 19],
          [ 5, 16,  2,  7, 15, 11, 18, 15, 18, 16],
          [ 3, 18, 17,  3, 19, 15,  6,  3,  8, 18],
          [15,  5, 10, 17, 13,  6,  3, 19,  5, 10]], dtype=int64) 

我想用seed=5的生成器在这个矩阵中添加10个零。我想用dimessions[5,10]创建一个新数组，在里面放10个0，剩下的是一个，然后把两个数组混合起来，但是我必须使用生成器，所以我不能这样做。

Answer 1

尝试使用np.random.choice选择索引，然后将这些索引处的值设置为0:

np.random.seed(10)
idx = np.random.choice(np.arange(5*10), size=5, replace=False)

rng.ravel()[idx] = 0

输出：

array([[15, 19,  6,  4, 16, 16, 10,  3, 16, 10],
       [ 3,  3,  8, 14,  8, 16,  1,  9, 10, 19],
       [ 5, 16,  2,  0, 15, 11, 18, 15, 18, 16],
       [ 3, 18, 17,  3, 19, 15,  6,  0,  8, 18],
       [15,  5,  0, 17,  0,  6,  3,  0,  5, 10]])