MATLAB: Repeating a row vector in MATLAB until it reaches a specified length.

repeatingrow

Suppose I have 2 single row vectors j and k, such that the length of j > the length of k

The problem: I want to make the length of k= the length of j in such a way that the elements in k keep repeating themselves until the length of k = the length of j.

Example:

j=[1,2, 3, 4, 5, 6, 7]; k=[-1,3,4];

After the program runs, it should return:

k=[-1,3,4,-1,3,4,-1];

How can this be accomplished in MATLAB? The more ways there are to implement this program (loops, if statements, logical indexing, etc.) the merrier.

Regards,

Best Answer

Here is one way to do it

k_new = k(mod(0:length(j)-1,length(k))+1)

HTH

Related Solutions

MATLAB: Linear Problem Matrix without For Loop

Hello all.! thank you for your answers!! I think I found it,with your help.

K = [1 2 4 3 4 6 ];
  [~,n]=ismember((K),unique(K));
  L=zeros(length(K),length(unique(K)))
  L(sub2ind(size(L), 1:length(K(1,1:end)),n))= 1

if there's something better I'll be glad to see it.! Thank you all!

MATLAB: Unable to calculate xcorr in for loop

A simplification to avoid repeated calculations:

L = size(wg1, 1);  % Better than: length(wg1(:,k))

for k = 2:numel(rep)
    X(k)         = xcorr(wg1(:,1), wg1(:,k));
    [m(k), d(k)] = max(X(k)); 
    delay(k)     = d(k)-max(L);
    tX(k)        = (delay(k)+1:L + delay(k)) ./ Fs;
end

I've replaced the square brackets by parentheses, see http://www.mathworks.com/matlabcentral/answers/35676-why-not-use-square-brackets

Now look on the assignment of tX(k): On the right side is a vector, and on the left side a scalar. Then the assignment cannot work. To store vectors of different lengths you need a cell array:

L = size(wg1, 1);  % Better than: length(wg1(:,k))
tX = cell(1, numel(rep));
for k = 2:numel(rep)
    X(k)         = xcorr(wg1(:,1), wg1(:,k));
    [m(k), d(k)] = max(X(k)); 
    delay(k)     = d(k)-max(L);
    tX{k}        = (delay(k)+1:L + delay(k)) ./ Fs;
end

But wait! xcorr replies a vector also. Then "X(k) = xcorr(...)" suffers from the same problem also. It would be more clear, which line causes the troubles, if you post the complete error message, which mentions all details. If you just post a tiny part of the message, the readers have to guess the details - inefficient.

Best Answer

Related Solutions

MATLAB: Linear Problem Matrix without For Loop

MATLAB: Unable to calculate xcorr in for loop

Related Question