我如何编写一个函数f(v, n)
(或使用基数R函数),该函数将数字矢量v
转换为另一个基于n
的循环因子(缺少更好的单词)。例如:
f(v = c(1,2,3,4,5), n = 1) #would yield c(1,2,3,4,5)
f(v = c(1,2,3,4,5), n = 2) #would yield c(1,2,1,2,1)
f(v = c(1,2,3,4,5), n = 3) #would yield c(1,2,3,1,2)
f(v = c(5,4,3,2,1), n = 3) #would yield c(2,1,3,2,1)
f(v = c(3,6), n = 3) #would yield c(3,3)
我最近得到的是使用%%
1:5%%3 #giving me: [1] 1 2 0 1 2 - not quite what I want, at least some recycling.
我们可以将函数创建为
f <- function(x, n) if(n ==1) x else (x - 1) %% n + 1
f(1:5, 1)
#[1] 1 2 3 4 5
f(1:5, 2)
#[1] 1 2 1 2 1
f(1:5, 3)
#[1] 1 2 3 1 2
f(5:1, 3)
#[1] 2 1 3 2 1