How to calculate the sum of particular row in a matrix??

6 次查看（过去 30 天）

Bibek Dhami 2020-7-28

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/571834-how-to-calculate-the-sum-of-particular-row-in-a-matrix

评论： Star Strider 2020-7-28

I have a large matrix A with the dimension 1024 X 256. I want to add the elements of the 104th row from column 25 to 75. I tried this code but it doesn't work. Can someone please guide me on this?

B= sum(A(104, 25:75)

采纳的回答

Star Strider 2020-7-28

2
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/571834-how-to-calculate-the-sum-of-particular-row-in-a-matrix#answer_472060

在 MATLAB Online 中打开

To sum across a row, specify dimension 2:

B= sum(A(104, 25:75),2)

That should do what you want.

If I individually perform these operations, I can get the value. But I have 400 such files in the folder and I need these 400 values as you obtained for this particular file(206685). That's why I am trying to use for loop in the first case.

Star Strider 2020-7-28

I understand.

The problem is that my ability to help you with the file problem is significantly limited. That is the reason that I encourage you to determine what is in ‘F’ before the loop and in each iteratiion, and what is in ‘file’ in each iteration. You simply need to list ‘F’ to determine what it is, and list every value of ‘F(i).name’, at least for the first few (perhaps 10) iterations, until the first loop works as you want it to work. One way to determine what is in ‘file’ is to use the size and nnz functions to see what is in it.

请先登录，再进行评论。