How to apply a function to every consecutive n elements in a vector

Question

I am trying to convert quarterly returns to yearly returns. Given a vector of quarterly returns, how can this be done?

I am fairly new to R-programming, so I haven\'t r

Answer 1

Using apply:

apply(matrix(a, nrow = 4), 2, function(x) prod(1 + x) - 1)
#[1] 0.2578742 0.180033