Select repeating elements in an matrix

I have this matrix:

1 44

1 24

2 56

1 26

2 51

2 56

I want to select all rows whose first column is a one.

That is, I want to get an array:

1 44

1 24

1 26

and on the other hand:

2 56

2 51

2 56

Thank you very much for the help

Answer 1

[Sulaymon Eshkabilov]

A = [???] % Your data

B = A(A(:,1)==1, :)

Good luck

[Maria Jesús Pérez Saiz]

Thank you very much for the help

[Sulaymon Eshkabilov]

Most Welcome! It is just a pleasure to help.