31-transformationsandadjustments.R

library(fpp3)

global_economy |> 
  filter(Country == 'United Kingdom') |>
  autoplot(GDP / Population)

print_retail <- aus_retail |>
  filter(Industry == "Newspaper and book retailing") |>
  group_by(Industry) |>
  index_by(Year = year(Month)) |>
  summarise(Turnover = sum(Turnover))

print_retail |> autoplot()

aus_economy <- global_economy |>
  filter(Code == "AUS")

aus_economy

print_retail |> left_join(aus_economy, by ="Year") |>
  mutate(Adjusted_turnover = Turnover / CPI * 100) |>
  pivot_longer(c(Turnover, Adjusted_turnover), values_to = "Turnover") |>
  mutate(name = factor(name, levels =c("Turnover", "Adjusted_turnover"))) |>
  ggplot(aes(x= Year, y = Turnover)) +
  geom_line() +
  facet_grid(name ~., scales = "free_y") +
  labs(title = "Turnover: Australian print media industry", y = "$AU")

food <- aus_retail |>
  filter(Industry == "Food retailing") |>
  summarise(Turnover = sum(Turnover))

food |> autoplot(log(Turnover)) +
  labs(y = "Log turnover")

food |> features(Turnover, features = guerrero)

lambda <- aus_production |>
  features(Gas, features= guerrero) |>
  pull(lambda_guerrero)
aus_production |>
  autoplot(box_cox(Gas, lambda)) +
  labs(y = "",
       title = latex2exp::TeX(paste0(
         "Transformed gas production with $\\lambda$ = ",
         round(lambda,2))))