如何用索引替换矩阵中的值

Question

假设我有一个4X4矩阵，包含从1到20的值。如果我想让第二行第三列的元素等于100，我该怎么做呢?

Answer 1

First, import the numpy library:
import numpy as np
Then, create the matrix:
matrix = np.array([[1,2,3], [4,5,6], [7,8,9]])
Finally, use the index to replace the value:

矩阵[1,2]= 10

The new matrix will be:
[[ 1  2  3]
[ 4  5 10]
[ 7  8  9]]