substract an element from previous element in a matrix

i have a k vector that contains 5 elements.

i want to write a code that substract - the second element from first

- the third element from second

- the fourth element from third

- the fifth element from fourth

and put them all in a vector form that will contain 4 elements

b=[k(2)-k(1) k(3)-k(2) k(4)-k(3) k(5)-k(4)];

how can i do that?

Answer 1

[Star Strider]

The diff function seems to be appropriate.

[Mahmoud Chawki]

How about if i want to substract the square of each element minus the square of the previous one?

[Torsten]

b = diff(k.^2)

[Star Strider]

@Torsten — Thank you!