element wise operation column matrix

I have a column matrix of data , Temp_data= [20;27;29;33;40] , i want to subtract each element i, by the first element (i.e 20-20; 27-20; 29-20;33-20), how do i do this?

also, how to do the similar operation if i have to subtract consequtive elements, i.e A(n) - A(n-1) [ex: 20-20; 27-20; 29-27....]

Answer 1

[Stephan]

Temp_data= [20;27;29;33;40]

Temp_data = 5×1

20 27 29 33 40

Case_1 = Temp_data - Temp_data(1)

Case_1 = 5×1

0 7 9 13 20

Case_2 = diff(Temp_data)

Case_2 = 4×1

7 2 4 7

Answer 2

[Stephen23]

T = [20;27;29;33;40];
A = T - T(1)

A = 5×1

0 7 9 13 20

B = [0;diff(T)]

B = 5×1

0 7 2 4 7

[Stephan]

I thought about adding zero as first elemnt, since it is part of the desired result. But i think it does not meet the rquirement of A(n) - A(n-1) - so we'll see