convert Vector into matrix ?
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Alex
le 24 Mai 2013
Réponse apportée : Stephen23
le 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 ??
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Réponse acceptée
Youssef Khmou
le 24 Mai 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
3 commentaires
Mohammed Ghouse Mohiuddin
le 31 Mar 2021
For loops are too complex for me. I hate it. Nobody explains it to me in a logical way.
Image Analyst
le 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.
Plus de réponses (6)
Image Analyst
le 24 Mai 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)]
Matt Kindig
le 24 Mai 2013
Modifié(e) : Matt Kindig
le 24 Mai 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))
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Youssef Khmou
le 25 Mai 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
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Youssef Khmou
le 25 Mai 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;
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anukriti dureha
le 25 Mai 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);
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