Suppose I have a data frame 'country' with 3 colums:
My objective is to grow the GDP and population for the next five years according to assumptions. I have developped the following loop:
country[19:23,1] <- seq(2018, by=1, length.out = 5)
for (i in 19:nrow(country)){
country[i,"GDP"] <- country[i-1, "GDP"] * (1 + hypo_gdp/100)
country[i,"Population"] <- country[i-1, "Population"] * (1 + hypo_pop/100)
}
Where hypo_gdp and hypo_pop are my growth assumptions.
Is there a way to use one of the apply() functions in this case?
Thanks in advance!
You do not need any apply() function in this case. This is just a simple geometric progression:
# simulate some data
country <- data.frame(year = 2000:2017,
GDP = rep(100, 18),
Population = rep(1000, 18))
country[19:23,1] <- seq(2018, by=1, length.out = 5)
# define gdp and pop parameters
hypo_gdp = 5
hypo_pop = 2
# define common ratios
b1 <- (1 + hypo_gdp/100)
b2 <- (1 + hypo_pop/100)
# calculate values for years 2018-2022
country[19:23,2] = country$GDP[18]* b1 ^ (1:5)
country[19:23,3] = country$Population[18]* b2 ^ (1:5)
tail(country)
# year GDP Population
# 18 2017 100.0000 1000.000
# 19 2018 105.0000 1020.000
# 20 2019 110.2500 1040.400
# 21 2020 115.7625 1061.208
# 22 2021 121.5506 1082.432
# 23 2022 127.6282 1104.081