How to calculate returns from a vector of prices?

Question

I have to calculate the return of a vector that gives a historical price series of a stock. The vector is of a form:

a <- c(10.25, 11.26, 14, 13.56) 
         


        

Answer 1

Another possibility is the ROC function of the TTR package:

library(TTR)
a <- c(10.25, 11.26, 14, 13.56)
ROC(a, type = "discrete")
## [1]          NA  0.09853659  0.24333925 -0.03142857

type = continuous (which is also the default) gives log-returns:

ROC(a)
## [1]          NA  0.09397892  0.21780071 -0.03193305