How to find some specific values of an array in another matrix ?

Hi, I have one <4X2> matrix that looks like x=[2 3 7 8 (Column1), 10 20 30 40(Column2)]. I have another <39X2> matrix that looks like y= [2:40 (column1), 39 specific values in column2]. I would like to find the column1 values of matrix x (2,3,7,8) in matrix y column1 (2:40) and then save the corresponding matrix y column2 values in a new matrix y1. For example: y1=[2 3 7 8, the corresponding specific values from the column2 of y matrix].

Special note: the values of matrix x=[2 3 7 8 (Column1), 10 20 30 40(Column2)] may change in different situations. So, it can also be x=[3 7 9 11, 30 50 70 90] at another time. But the matrix y is always fixed with same values.

Thank you so much for helping me out.

[Azzi Abdelmalek]

Your question is hard to read. Post an example without writing (column 1), we know it's column 1. And post what is the expected result.

[Maruf]

Thanks for your comment. I have attached an illustration here. Does it help? :)

Answer 1

[Azzi Abdelmalek]

x=[ 2 10
3  20
7  30
8  40]
y= [2 0.2
3  0.3
4  0.2
5  0.2
6  0.2
7  0.5
8  0.6
9  0.2]
result_y1=y(ismember(y(:,1),x(:,1)),:)

[Maruf]

It works perfectly. Thanks a lot for your help :D