How to get a value for the next year

Considering the following dataset:

What I want to do is to measure the future return of the customers. So, I need to have the customer amount of next year in a new column. Something like this:

Does anybody have any idea how to do this?

>Solution :

You can use lead like in the following code:

library(dplyr)
df %>%
  group_by(Company) %>%
  mutate(customers_next_year = lead(Customers)) %>%
  ungroup()

Output:

# A tibble: 9 × 4
# Groups:   Company [3]
  Company  Year Customers customers_next_year
  <chr>   <dbl>     <dbl>               <dbl>
1 A        2018       100                 120
2 B        2018       120                 180
3 C        2018       150                  80
4 A        2019       120                 200
5 B        2019       180                 500
6 C        2019        80                 140
7 A        2020       200                  NA
8 B        2020       500                  NA
9 C        2020       140                  NA

Data

df <- data.frame(Company = rep(c("A", "B", "C"), 3),
                 Year = c(2018, 2018, 2018, 2019, 2019, 2019, 2020, 2020, 2020),
                 Customers = c(100,120,150,120,180,80,200,500,140))