I have an array of repetitive values something like A=[0;0;396; ...;140;... ;403; 0 ;0 ;0 ;200; 140; ...;403; 0; 0 ] . I extracted non-zero set of data to another array, called B=[396; ...;140;... ;403 , 200; 140; ...;403]. Now, I want to find the index of each set of elements of array B from array A, but when I use '[tf,idx] = ismember (B,A)' , what is happening is that for those repeated elements the index is always the same as the index of first appeared one (idx for second 140 or 403 is the same of the idx of the first ones!). So, my question is that how can I find the indexes based on order ? or how can I find indexes when all the elements of array B's columns exactly repeated in array A?