Hi Samaneh,
My understanding of your question is that for the vectors X and Y you want to find values which are common in both.
For that you can use
intersect
Example snippet:
x=[1 2 3 4 5 10 20 30];
y=[4 5 10 100 90 22 33];
[z ix iy]= intersect(x,y)
x(ix)=[]
y(iy)=[]
