find common elements of two arrays

Dear all,

I have two arrays of different size say A(nx1) and B(mx1) where n differs from m. I would like to find the elements of B that are as close as possible to the element of A and display them. How can I do that please? Most of matlab applications I found (equal, ismember, find, etc) they require arrays of the same size which is not my case. Thank you very much for any guidance or advice you could give me

Regards

S

Answer 1

[Chris A]

a=[5; 7; 3; 1; 8; 6; 2];
b=[3; 9; 0];
d=repmat(a,1,numel(b)) - repmat(b', numel(a),1);
[~,i]=min(abs(d));
horzcat(b, a(i)),  % Closest elements to b

Answer 2

[Matt J]

ISMEMBER doesn't require the arguments to be the same size and neither does this.

Answer 3

[Daniyal Awan]

Another way. The tolerance is the difference you allow. a must be smaller or equal in length to b. I like circshift, even though for loop can hurt in case of long vectors

 function closest(a,b,tolerance)

 c=[];

 if (length(a)<=length(b))

    a=[a nan*ones(1,length(b)-length(a))];

    for shift=1:length(a)

        c=[c ; b(abs(b'-circshift(a',shift))<tolerance+1)'];
    end

 else

    error('beep..wrong order of input vectors!!')

 end

 disp(c)