I have a 5x6 matrix. I want to calculate sum of only those values which are consecutive nonzero along each row. How to do that? The desired result given in description box.

Question

Payel 2023-6-24

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1987678-i-have-a-5x6-matrix-i-want-to-calculate-sum-of-only-those-values-which-are-consecutive-nonzero-alo

评论： Image Analyst 2023-6-24

a = [2 3 1 4 0 0;
     0 0 0 0 0 0;
     0 0 1 5 7 0;
     0 0 0 0 4 0;
     4 5 0 0 6 8];
desired_result = [10;0;13;0;23]
desired_result = 4×1
    10
     0
    13
     0

4 个评论
显示 2更早的评论隐藏 2更早的评论

Payel 2023-6-24

The result of 4th row is not 4 because I want summation of only consecutive non zero values along each row.

The desired result of a should be 17

the cyclist 2023-6-24

I believe a correct re-statement of the rule is, "Sum all non-zeros that are next to at least one other non-zero."

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

the cyclist 2023-6-24

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1987678-i-have-a-5x6-matrix-i-want-to-calculate-sum-of-only-those-values-which-are-consecutive-nonzero-alo#answer_1261828

编辑：the cyclist 2023-6-24

在 MATLAB Online 中打开

I believe this does what you want:

% Input
a = [2 3 1 4 0 0;
     0 0 0 0 0 0;
     0 0 1 5 7 0;
     0 0 0 0 4 0;
     4 5 0 0 6 8];
% Append columns of zeros at both ends, because we are going to check in
% the next line if an element is a "singleton" with zeros on both sides
b = [zeros(height(a),1) a zeros(height(a),1)];
% Identify the non-singleton value (i.e. the ones that do not have zeros on either side)
includeInSum = not((b(:,1:end-2) == 0) & (b(:,3:end)==0));
% Sum the values that should be included
result = sum(a.*includeInSum,2)
result = 5×1
    10
     0
    13
     0
    23

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

Answer 2

Image Analyst 2023-6-24

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1987678-i-have-a-5x6-matrix-i-want-to-calculate-sum-of-only-those-values-which-are-consecutive-nonzero-alo#answer_1261808

在 MATLAB Online 中打开

a = [2 3 1 4 0 0;
    0 0 0 0 0 0;
    0 0 1 5 7 0;
    0 0 0 0 4 0;
    4 5 0 0 6 8];
desired_result = [10;0;13;0;23]
desired_result = 5×1
    10
     0
    13
     0
    23
desired_result = sum(a, 2)
desired_result = 5×1
    10
     0
    13
     4
    23

To learn other fundamental concepts, invest 2 hours of your time here:

MATLAB Academy - Free 2 hour training

2 个评论
显示无隐藏无

Payel 2023-6-24

how to get the summation value of 4th row to be zero? as it is asked to find summation of only consecutive nonzero values along each row

Image Analyst 2023-6-24

Row 4 has one "consecutive' value, so why not sum it in? Do you want to sum in values only if the run of non-zero values is 2 or more? See @the cyclist's answer below. Is it homework? If so you can't use it.

This looks like a homework problem. If you have any questions ask your instructor or read the link below to get started:

How do I get help on homework questions on MATLAB Answers? - MATLAB Answers - MATLAB Central

Obviously we can't give you the full solution because you're not allowed to turn in our code as your own.

请先登录，再进行评论。