用numpy中的另一个小矩阵替换矩阵的子部分 [英] Replace sub part of matrix by another small matrix in numpy

问题描述

我是Numpy的新手，想替换矩阵的一部分.例如，我有两个由numpy生成的矩阵A，B

I am new to Numpy and want to replace part of a matrix. For example, I have two matrices, A, B generated by numpy

In [333]: A = ones((5,5))

In [334]: A
Out[334]: 
array([[ 1.,  1.,  1.,  1.,  1.],
       [ 1.,  1.,  1.,  1.,  1.],
       [ 1.,  1.,  1.,  1.,  1.],
       [ 1.,  1.,  1.,  1.,  1.],
       [ 1.,  1.,  1.,  1.,  1.]])

In [335]: B
Out[335]: 
array([[ 0.1,  0.2],
       [ 0.3,  0.4]])

最终，我想使A为以下矩阵.

Eventually, I want to make A be the following matrix.

In [336]: A
Out[336]: 
array([[ 1.,  1.,  1.,  1.,  1.],
       [ 1.,  1.,  1.,  1.,  1.],
       [ 1.,  1.,  1.,  1.,  1.],
       [ 1.,  1.,  1.,  0.1,  0.2],
       [ 1.,  1.,  1.,  0.3,  0.4]])

和/或以下

In [336]: A
Out[336]: 
array([[ 1.,  1.,  1.,  0.1,  0.2],
       [ 1.,  1.,  1.,  0.3,  0.4],
       [ 1.,  1.,  1.,  1.,  1.],
       [ 1.,  1.,  1.,  1.,  1.],
       [ 1.,  1.,  1.,  1.,  1.]])

我尝试按照以下步骤操作，但没有成功.我现在不知道:(

I tried like following but it didn't work. I don't have any idea now :(

A[[0,1],:][:,[3,4]] = B

甚至我尝试过

A[[0,1],:][:,[3,4]] = 1

检查是否更改了四个单元格.你有什么主意吗?

to check whether the four cell are changed or not. Do you have any idea?

推荐答案

以下是您的操作方法:

>>> A[3:5, 3:5] = B
>>> A
array([[ 1. ,  1. ,  1. ,  1. ,  1. ],
       [ 1. ,  1. ,  1. ,  1. ,  1. ],
       [ 1. ,  1. ,  1. ,  1. ,  1. ],
       [ 1. ,  1. ,  1. ,  0.1,  0.2],
       [ 1. ,  1. ,  1. ,  0.3,  0.4]])

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