matlab - number - Find given row in a matrix
matlab table column names (3)
gnovice's suggestion is even simpler than mine:
[~,indx]=ismember(X,M,'rows') indx = 3
M=magic(4); %#your matrix M = 16 2 3 13 5 11 10 8 9 7 6 12 4 14 15 1 X=[9 7 6 12]; %#your row vector find(ismember(M,X),1) ans = 3
I have an m by n matrix in
MATLAB, say M. I have an n-element row vector, i.e. a one by n column matrix, say X.
I know X is a row somewhere in M. How can I find the index in M?
Another solution that returns a row index for each occurrence of X is
Also, this solution can be easily adapted to find rows that are within threshold of X as follows (if numerical noise is an issue)
tolerance = 1e-16; %setting the desired tolerance find(sum(abs(M-ones(rows(M),1)*X),2)<tolerance)
This is a non-loop version. It is only suitable, if M (your matrix) is not very large, ie. n and m are small. X is your row:
function ind = findRow(M,X) tmp = M - repmat(X,size(M,1),1); ind = find(tmp,1); end
If M is too large, it might be faster, to iterate the rows of M and compare every row with your vector.
@Edit: renamed variables to match the names used in the question.