convert Vector into matrix ?

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 ??

Answer 1

[Youssef Khmou]

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

[Alex]

thank you ! I was trying to avoid the for, but i think is impossible, My final code is

N=32;
A=0:2*N-2;
t=A(1);
r=N-1;
for n=0:r
  B(n+1,:)=t:N-1+n;
  t=t+1;
end

[Mohammed Ghouse Mohiuddin]

For loops are too complex for me. I hate it. Nobody explains it to me in a logical way.

[Image Analyst]

@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.

TUTORIAL: How to ask a question (on Answers) and get a fast answer

Answer 2

[Image Analyst]

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]

i am sorry, my mistake, A is big, it was just an example, exist other way to make this automatic ??

Answer 3

[Matt Kindig]

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))

Answer 4

[Youssef Khmou]

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

Answer 5

[Youssef Khmou]

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;

Answer 6

[anukriti dureha]

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);

Answer 7

[Stephen23]

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