You can delete rows or columns of a matrix by assigning the empty matrix () to them. Try:
A(:, [2 4]) = 
In an array index expression, end denotes the index of the last element. Try:
x = rand(1,5)
x = x(end:-1:1)
MATLAB is a powerful and expressive language. To appreciate the usefulness of these features, compare these MATLAB statements with the equivalent code in C, Fortran, or Java.