How to split one column into multiple columns by delimiter (with different numbers of delimiter)

I have a dataframe like this one:

continent <- c("Europe", "Asia")
country <- c("France;Germany;Italy", "Japan")
start_problem <- data.frame(continent, country)
start_problem

I would like to seperate the values in the column country to multiple columns, one for every country. The end product should look like:

continent <- c("Europe", "Asia")
country1 <- c("France", "Japan")
country2 <- c("Germany", NA)
country3 <- c("Italy", NA)
goal <- data.frame(continent, country1, country2, country3)
goal

Using separate_wider_delim() does not work since not every continent has the same amount of countries, thus not the same amount of delimiters in the original column.

Thanks in advance

>Solution :

We can first find out how many columns are needed by finding the max number of occurrence of the delimiter ;. Then paste that information in the into = parameter of separate with the "country" string.

library(tidyverse)

col_number <- max(str_count(start_problem$country, ";") + 1)

start_problem %>% separate(country, 
                           into = paste0("country", seq_len(col_number)), 
                           sep = ";")

  continent country1 country2 country3
1    Europe   France  Germany    Italy
2      Asia    Japan     <NA>     <NA>