# Create matrix using the array as index

3 views (last 30 days)
HASAN AL-KAF on 8 Oct 2021
Answered: Rik on 8 Oct 2021
Hi,
I have an array of 1*2000 double. I want to create matrix of 6*2000 double. so only the index of the value is 1 and the others is zero in each columns.
for example if my array is a=[2 2 1 0 3]
the ouput of of matrix will be same as the image below?
Thank you.
##### 0 CommentsShowHide -1 older comments

Sign in to comment.

### Accepted Answer

Rik on 8 Oct 2021
You don't even need a loop:
a=[2 2 1 0 3];
ind=a+1;
A=zeros(max(ind),numel(ind));
ind=sub2ind(size(A),ind,1:numel(ind));
A(ind)=1
A = 4×5
0 0 0 1 0 0 0 1 0 0 1 1 0 0 0 0 0 0 0 1
##### 0 CommentsShowHide -1 older comments

Sign in to comment.

### More Answers (1)

per isakson on 8 Oct 2021
Try this
M = zeros(5,5);
a = [2,2,1,0,3];
for jj = 1:5
M(a(jj)+1,jj)=1;
end
disp(M)
0 0 0 1 0 0 0 1 0 0 1 1 0 0 0 0 0 0 0 1 0 0 0 0 0
##### 0 CommentsShowHide -1 older comments

Sign in to comment.

### Community Treasure Hunt

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

Start Hunting!