MATLAB: Consecutive subtraction of the entries of a vector

Question

I am a novist in MATLAB. I have no idea of how to subtract the entries of a vector consecutively. Say if A=[3,5,9,11,15]' and I want something like this B =[3, 2, 4, 2, 4]. Any help will do, thanks in advance.

Answer 1

If A is a row vector:

B = [A(1) diff(A)];

If A is a column vector:

B = [A(1);diff(A)];