# convert Vector into matrix ?

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Alex on 24 May 2013
Answered: Stephen23 on 31 Mar 2021
Hello, i need to convert a vector into matrix like this:
A = [1 2 3 4 5]
into
B=[1 2 3; 2 3 4; 3 4 5]
Any ideas ??

Youssef Khmou on 24 May 2013
hi Alex
This is not conversion but you are adding new elements to the original vector :
If you have a vector of size Mx1 you can convert it to matrix using function reshape to get a matrix of size PxN such M=P*N.
r=randn(100,1);
y=reshape(r,10,10);
In your case , try :
A=1:5;
t=1;
r=3;
for n=1:3
B(n,:)=t:n+2;
t=t+1;
r=r+1;
end
Image Analyst on 31 Mar 2021
@Mohammed Ghouse Mohiuddin, uncommented code (like Alex's) can be hard to understand. Everyone should use comments. If you can't figure it out, post a new question with the code you are trying to adapt and an explanation of what you really want to do (if you could adapt it). But read this link first.

Image Analyst on 24 May 2013
I know it seem really really obvious, but if that is all we have to go on (i.e. no indication that it needs to be generalized in any way), then why not just do this:
B = [A(1:3);A(2:4);A(3:5)]
Alex on 24 May 2013
i am sorry, my mistake, A is big, it was just an example, exist other way to make this automatic ??

Matt Kindig on 24 May 2013
Edited: Matt Kindig on 24 May 2013
It might not be very efficient, but I think it should work:
nc = 3; %number of columns in B
nc = nc-1;
c = 1:(length(A)-nc);
B = cell2mat(cellfun(@(n) A(n:(n+nc)), num2cell(c(:)), 'uni', false))

Youssef Khmou on 25 May 2013
hi, there are other alternatives , :
try :
N=32;
A=1:N;
A2=0:N-1;
A2=A2';
B=repmat(A,N,1);
for x=1:N
B(:,x)=B(:,x)+A2;
end

Youssef Khmou on 25 May 2013
hi,
here is the best solution without using loops :
N=32;
A=1:N;
B=repmat(A,N,1);
A2=(0:N-1)';
B2=repmat(A2,1,N);
C=B+B2;

anukriti dureha on 25 May 2013
hi alex, you can do this:
i=1;
ind=0;
num=3;
while num <=5
ind=ind+1;
z{i}=A(ind:num);
num=num+1;
i=i+1;
end
z=cell2mat(x);b=vec2mat(z,3);

Stephen23 on 31 Mar 2021
A = [1,2,3,4,5];
B = hankel(A(1:3),A(3:5))
B = 3×3
1 2 3 2 3 4 3 4 5