Here is a solution for Project Euler’s Problem #2 in R, which is stated as:

Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be:

1, 2, 3, 5, 8, 13, 21, 34, 55, 89, …

Find the sum of all the even-valued terms in the sequence which do not exceed four million.

Firstly ,we will define a function to calculate the Fibonacci numbers below N, where N in this case is 4*10^6:

fib < - function(n) { x <- c(length=10) x[1] <- 1; x[2] <- 2 for (i in 3:n) { y <- x[i-1]+x[i-2]; if (y > n){ break } else { x[i] < - y } } x }

Next, we just calculate the sum of the even-valued problems, in a similar manner to the way we solved problem #1:

f < - fib(4E6) sum(f[f %% 2 ==0])