How can I delete rows in a matrix where two numbers exist side-by-side?

I have a large matrix that has thousands of rows.

I need to delete the rows based on the following condition:

 >>> if in a row, ith column is 2 and (i+1)th column is 3

e.g. Input matrix [1, 2, 1; 1, 2, 1; 2, 2, 3]

Expected output: [1,2,1;1,2,1]

Answer 1

[lvn]

This should do the job. If you have a huge matrix and you want it to go faster, you will need to adapt this code to build up a vector with all rows that need deleting and do that once only (at the end).

A=[2,7,3;1, 2, 1; 1, 2, 1; 2, 2, 3; 1, 2, 1; 2, 3, 4]
rows=1;
while rows<=length(A)
if strfind(A(rows,:),[2 3])
    A(rows,:)=[];
end
rows=rows+1;
end
A

Output:

A =

       2     7     3
       1     2     1
       1     2     1
       2     2     3
       1     2     1
       2     3     4

A =

       2     7     3
       1     2     1
       1     2     1
       1     2     1

Answer 2

[Jos (10584)]

    A = [2,7,3;1, 2, 1; 1, 2, 1; 2, 2, 3; 1, 2, 1; 2, 3, 4]

    i = 1:size(A,2)-1 
    tf = A(:,i)==2 & A(:,i+1)==3 % true if i-the column is 2 and (i+1)th column is 3

    A(any(tf,2),:) = [] % remove those rows