deleting rows with a criteria for repeating indices

Hi All,

I have this matrix:

460231  1
406962  1
407721  1
407963  1
409590  1
480657  2
527635  2
525820  2
624575  2
593871  2
548098  3
542776  3
544329  3
553168  3
552825  3
473360  1
410370  1
408704  1
407852  1
409568  1
462219  2
510423  2
508923  2
508207  2
507325  2

and I want to do the following to the matrix. Can you please help me how to do it?

1- I want to remove all rows whose second column is 2.

2-For the remainder of the matrix, I want to delete the first two rows whose second column is 1 and 3

So, the output I want should look like this:

407721  1
407963  1
409590  1
544329  3
553168  3
552825  3
408704  1
407852  1
409568  1

Answer 1

[Stephen23]

>> B = A(A(:,2)~=2,:);
>> X = diff(B(:,2))~=0;
>> X = [true;X] | [true;true;X(1:end-1)];
>> C = B(~X,:)
C =
   407721        1
   407963        1
   409590        1
   544329        3
   553168        3
   552825        3
   408704        1
   407852        1
   409568        1

[masih]

Great!