How to search through a matrix.

Hello, I have two matrices. One is a 388 x 4 called data and the other is a 31 x 3 called num. Both matrices have column 1 being Latitude values, column two being Longitude values and column 3 being Rainfall values. I need to search through column 1 & 2 of the data matrix to find the Lat & Lon values corresponding to those in the num matrix, then take the value in the 3rd column(Rainfall) of the data matrix that aligns with the Lat/Lon coordinates and stick it into a new array that is 31 x 1 (to match with the size of the rainfall column in the num matrix).

[Brandon Bush]

I found a function called intersect(A,B). i believe this will help to find matching values but I am not sure where to go from there.

Answer 1

[Matt J]

Only 31 look-ups? For things like that, for-loops are fine:

 newarray=nan(31,1);

 for i=1:31

    j=find( data(:,1)==num(i,1)  &  data(2,:)==num(i,2) );

    if ~isempty(j)
       newarray(i)=data(j,3);
    end

 end

[Brandon Bush]

Thank you, this works like a charm