# Replacing elements in Array

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Angela on 20 Jul 2012
I have two 48 x 61 matrices, LE and Q. If the first and last row value of LE are the same, for those rows, I want the values of Q to equal Q(:, 61).
This is what I initially wrote, but am getting an error message.
C = find(LE(:,1) == LE(:,61)); % Outputs rows in which first and last values are equivalent.
Q(C,:) = Q(C, 61); % For all values in rows C, make every value in that row (of Q) the last value in row Q.
Error: subscript assignment dimension mismatch.
Any suggestions? Thanks!
##### 1 CommentShowHide None
Image Analyst on 20 Jul 2012
It's always nice if the poster supplies some sample data in advance to make it easy for people to try things for her. I mean, why make it hard for people to help you?

Jan on 20 Jul 2012
Q(C, :) = repmat(Q(C, 61), 1, size(Q, 2));

### More Answers (1)

Albert Yam on 20 Jul 2012
When length(C) > 1 , Matlab doesn't know how to replace the values.
(length(C) x 61) matrix , and a length(C) vector
If you loop it for every C, it should work, someone else might be able to point out a way without looping.
C = find(LE(:,1) == LE(:,61));
for ii=1:length(C)
Q(C(ii),:) = Q(C(ii), 61);
end