Accessing column elements in a 2D array

In reply to dave_59:

Hi Dave,

Could you please explain what below lines do? I checked the array reduction methods but I am having hard time to understand array reduction methods when used with ‘with’ clause. Also col.index?

matrix.and(col) with (matrix[col.index][k] == 1)
matrix.and(col) with (matrix[col.index][k] == 0)

I tried to run above code but could not make sense of the output.