Max value of row in matrix and creating new matrix

1 次查看（过去 30 天）
Etan Cole
Etan Cole 2014-10-7
评论： Star Strider 2014-10-8
I want something like this matrixa=[12 33 44;26 59 14;15 99 54] matrixb=[26 89 95;23 54 12;2 54 43]
and to get output like this
matrixc=[15 99 54;26 89 95]
calculate the sum of rows in both matrix and to create a new matrix with the two rows that have the greatest sum value like example above. can it be done with max function ? thanks in advance :)
  2 个评论
Etan Cole
Etan Cole 2014-10-7
clear; a=[15 9 7;8 5 5;1 7 4]; b=[6 5 9;8 2 5;5 4 4]; [C,I]=max(sum(a,1)); [C1,I1]=max(sum(b,1)); matrix=[a(I,:);b(I1,:)];

请先登录，再进行评论。

请先登录，再回答此问题。

回答（2 个）

Star Strider
Star Strider 2014-10-7
This works:
sa = sum(matrixa,2);
sb = sum(matrixb,2);
c = zeros(size(matrixa));
q1 = matrixa(sa > sb,:);
q2 = matrixb(sb > sa,:);
c(sa > sb,:) = matrixa(sa > sb,:);
c(sb > sa,:) = matrixb(sb > sa,:);
  3 个评论
显示 1更早的评论
Star Strider
Star Strider 2014-10-7
Misread it at first. This works:
sa = sum(matrixa,2);
sb = sum(matrixb,2);
mab = [matrixa; matrixb];
sab = [sa; sb];
[srtab,ix] = sort(sab,'descend');
matrixc = mab(ix(1:2),:);
Star Strider
Star Strider 2014-10-8
With respect to your solution, what happens if the two largest row sums happen to be in the same matrix?
My code accounts for that, so that ‘c’ contains the rows of either matrix with the largest row sums.
Your code selects the largest row sums from ‘matrixa’ and ‘matrixb’. They may not be the largest row sums of the two matrices.

请先登录，再进行评论。

Etan Cole
Etan Cole 2014-10-7
i got it working like this. thanks for the help
[C,I]=max(sum(a,2)); [C1,I1]=max(sum(b,2)); rezultat=[a(I,:);b(I1,:)];

类别

在 Help Center 和 File Exchange 中查找有关 Creating and Concatenating Matrices 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by