How to dynamically update the matrix ?
显示 更早的评论
Hello Guys,
I have to generate matrix A=[-1 0 c1; 0 -1 c2] dynamically, for example if c1=[1 1 2 2] & c2=[3 3 4 4] are 1d arrays and if its length change after every execution of loop then the output of matrix A will increase automatically after increase in length of c1 & c2 arrays, for example in case of above example the output of A will be like...
A = [-1 0 1;
0 -1 3;
-1 0 1;
0 -1 3;
-1 0 2;
0 -1 4;
-1 0 2;
0 -1 4;]
How do i write this type of matrix dynamically ?
采纳的回答
Weird Rando
2016-5-8
编辑：Weird Rando
2016-5-8
This only works if c1 and c2 have the same length
A = [];
c1=[1 1 2 2];
c2=[3 3 4 4];
nloop = length(c1);
for ii = 1:nloop
A=[A;-1 0 c1(ii); 0 -1 c2(ii)]
end
4 个评论
Ahsan Abbas
2016-5-8
Ced
2016-5-8
You can transform c1 and c2 into matrices before concatenation. There is no need for the for loop.
A = [ 1 2 ; 3 4];
c1 = {1,1,2,2};
c2 = {3,3,4,4};
c1_num = cell2mat(c1);
c2_num = cell2mat(c2);
A = horzcat(A,[c1_num; c2_num]);
or, directly
A = [ 1 2 ; 3 4];
c1 = {1,1,2,2};
c2 = {3,3,4,4};
A = [ A cell2mat([c1 ; c2]) ]
Note that c1_num and c2_num must have the same number of columns, and their total number of rows should equal the number of rows of A. Also, the cells must only contain numerical scalars, but I suppose that's fairly obvious.
Image Analyst
2016-5-8
There is also no need, that you've shown so far, for a cell array. A simple numerical array would be much simpler and easier.
Ahsan Abbas
2016-5-8
更多回答（0 个）
类别
在 帮助中心 和 File Exchange 中查找有关 Matrix Indexing 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
