MATLAB: How to select certain columns of a matrix only when the first two rows always show 1 and the other two rows a 0

conditionextract columns

Hi everybody!
I have a Matrix with 4 rows and 922 columns M(4,2300) containing ones and zeros as shown below
1 0 1 1 ...
1 0 1 1 ...
0 0 0 1 ...
0 0 0 0 ...
I want to keep only the columns when the first two rows show a 1 and row three and four show a zero.
In the example above column 1 and 3 fulfill the conditions whereas column 2 and 4 don't.
Does somebody have a nice idea to write a simple code to extract the columns to have an output for the example above like: [1 0 1 0]?
Thanks a lot for your help guys!!!

Best Answer

  • Hi,
    Use:
    col = find(all(matrix(1:4,:)==[1;1;0;0]))
    This will give you all the columns that satisfy this condition. You can then use
    matrix(:,col)
    to extract those columns from the matrix.
    Hope this helps!