Creating a pivot table

Question

Suppose I have a dataset that looks like the following, in which years are listed down rows:

id<-c(1,1,1,2,2,2,3,3,3)
year<-c(1990, 1991, 1992, 1992, 1         


        

Answer 1

these days using tidyverse is more the rage:

library(tidyr)

dataset %>% 
  spread(year, N, fill = 0)