How to find two points with same x coordinate when two graphs are plotted in a same plot?

Hello everyone. I need a help from you all. I am trying to plot two different graphs (say G1 and G2) in a same plot using hold on command. Now, I have marked a point on G1 say P1(x,y). I want to find the point P2(x,y) on the other graph G2 for same x coordinate. What commands I can use to achieve this? I hope my question is clear to you and can anyone please help me? Thanks in advance.

Answer 1

[Meade]

Give this a shot:

    n = 1% The number of identical 'x' coordinates you want to find, delete "n" to find them all
    idx = find(G2(:,1) == P1(1,1),n);   % Finds the idx of the points in G2 matching P1(x)
    P2 = G2(idx,:)                      % Assigns all matching points in G2 to P2;

or more concisely:

P2 = G2(G2(:,1) == P1(1,1),:)