Remove elements from an array

hi,

I have row IDs (or row numbers) of an array. i.e. k=[60:1462:3652136]. I have my YY array [3652500 x 2]. How can I remove the rows of k from YY and store in a different array called XX [2499 x 2].

Can somebody help me with that?

Thanks,

Dumindu.

Answer 1

[dpb]

XX=YY(k,:);

I pointed you to this earlier I believe -- look up "logical addressing" in the documentation; it's still a key portion of Matlab syntax.

[Damith]

Thanks. But gives me an error "Index exceeds matrix dimensions". First I need to remove rows in k from YY array and then store in XX.

[dpb]

You've got indices in k that exceed the size(XX,1) so you've got to redefine what you mean.

The length(k) is, as you say, 2499, but from 3652501 on there aren't rows in YY to remove.

I see two ways you can go --

1) If you can live with whatever is in the result array that exists already in YY irrespective of the total elements in XX, then

k=[60:1462:length(YY)];

2) If it's mandatory to have 2499 elements in XX, then

XX=zeros(2499,2);   % initialize, any value is ok (use nan(), say)
XX(k,:)=YY(k,:);    % k as above

Any similar workaround just so you don't try to reference non-existent elements.