CODEWITHSUNDEEP
arraysmatlabmatrix
EyesOfÖzil
EyesOfÖzil

Reputation: 309

How to reshape column matrix according to the row size of another matrix in matlab

I have one column matrix as follows

P = [1;2];

I Have another column matrix Q which has to be added to the first matrix. But the number of rows in second column matrix is always more than that of P

Q = [4;5;6];

i want to split or reshape Q according to size of P . if size of P is n , then first n elements of Q goes into the second column of output and the remaining elements to third coulmn while the first column of output is nothing but P

I need the output as below but I cannot use the reshape as I am not sure of the size of both matrices as they can vary.

output = [1 4 6;2 5 0];

Could someone assist me?

Thanks

Upvotes: 1

Views: 177

Answers (3)

Some Guy
Some Guy

Reputation: 1797

You can also append the required number of zeros within the reshape statement itself, resulting in a single line solution

R = [P reshape([Q; zeros(numel(P) - mod(numel(Q),numel(P)),1)],numel(P),[])]

Upvotes: 1

user2261062
user2261062

Reputation: 

% first we fill Q with appropiate number of zeros 
% (basically we see how many times Q is bigger than P rounded up)   
new_Q = zeros(numel(P)*ceil(numel(Q)/numel(P)), 1);
new_Q(1:numel(Q)) = Q;

% then we create a new matrix containing `P` and the reshaped `new_Q`

R = [P reshape(new_Q, [numel(P), numel(new_Q)/numel(P)])]

R =

     1     4     6
     2     5     0

This will work for any size of P and Q if they are both initially vectors (not matrices)

Upvotes: 2

Luis Mendo
Luis Mendo

Reputation: 112679

If you have the Communications Toolbox, use vec2mat:

result = vec2mat([P(:); Q(:)], numel(P)).';

Upvotes: 2

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