Select all eelements equal to a number

I have an array of elements x= [1 1 1 1 1 1 2 2 2 2 2 2 3 3 3 3 3 4 4 7 7 4 4 4 5 5 5 5 6 6 6 6 7 7 7 7];

I want to write a script that starts checking the array from the last element and when this is equal to 4 , it breaks and returns the rest of the array say b= [1 1 1 1 1 1 2 2 2 2 2 2 3 3 3 3 3 4 4 7 7 4 4 4];

Please any help.

Thank you.

Answer 1

[Adam]

b = x( 1:find( x == 4, 1, 'last' );

[Daniel Boateng]

thank you very much