Spreading a Column to Find Largest/Smallest Observations - r

Question

Currently struggling with a problem finding the country where billionaires are the oldest and youngest on average in a given country (data set shown below).
Moreover, I need to remove countries that have less than five observations.
I have code below that shows a table of age, worth in billions, and country code. I have countries sorted, but I am unsure of the best strategy to find which country has the youngest/oldest billionaires.
I have one line struck out where I am trying to spread by country name, but I think that will probably be messy.
Small sample here:
# A tibble: 2,614 x 22
age category citizenship company.name company.type `country code` founded
<int> <chr> <chr> <chr> <chr> <chr> <int>
1 NA Financi… Saudi Arab… Rolaco Trad… new SAU 1968
2 34 Financi… United Sta… Fidelity In… new USA 1946
3 59 Non-Tra… Brazil Companhia B… new BRA 1948
4 61 New Sec… Germany Ratiopharm new DEU 1881
5 NA Financi… Hong Kong Swire new HKG 1816
6 NA Traded … Bahrain YBA Kanoo new BHR 1890
7 NA New Sec… Japan Otsuka Hold… new JPN 1921
8 NA Traded … Japan Sony new JPN 1946
9 66 Financi… Japan Mori Buildi… new JPN 1959
10 NA Traded … France Chanel new FRA 1909
# … with 2,604 more rows, and 15 more variables: `from emerging` <chr>,
# gdp <dbl>, gender <chr>, industry <chr>, inherited <chr>, name <chr>,
# rank <int>, region <chr>, relationship <chr>, sector <chr>, `was
# founder` <chr>, `was political` <chr>, wealth.type <chr>, `worth in
# billions` <dbl>, year <int>
dput(head(bil))
structure(list(age = c(NA, 34L, 59L, 61L, NA, NA), category = c("Financial",
"Financial", "Non-Traded Sectors", "New Sectors", "Financial",
"Traded Sectors"), citizenship = c("Saudi Arabia", "United States",
"Brazil", "Germany", "Hong Kong", "Bahrain"), company.name = c("Rolaco Trading and Contracting Company",
"Fidelity Investments", "Companhia Brasileira de Distribui?ao",
"Ratiopharm", "Swire", "YBA Kanoo"), company.type = c("new",
"new", "new", "new", "new", "new"), country_code = c("SAU", "USA",
"BRA", "DEU", "HKG", "BHR"), founded = c(1968L, 1946L, 1948L,
1881L, 1816L, 1890L), `from emerging` = c("True", "True", "True",
"True", "True", "True"), gdp = c(1.58e+11, 8.1e+12, 8.54e+11,
2.5e+12, 1.6e+11, 6.1e+09), gender = c("male", "female", "male",
"male", "male", "male"), industry = c("Money Management", "Money Management",
"Retail, Restaurant", "Technology-Medical", "Money Management",
"Consumer"), inherited = c("True", "True", "True", "True", "True",
"True"), name = c("Abdul Aziz Al-Sulaiman", "Abigail Johnson",
"Abilio dos Santos Diniz", "Adolf Merckle", "Adrian and John Swire",
"Ahmed Ali Kanoo"), rank = c(404L, 145L, 322L, 388L, 162L, 383L
), region = c("Middle East/North Africa", "North America", "Latin America",
"Europe", "East Asia", "Middle East/North Africa"), relationship = c("founder",
"relation", "relation", "relation", "relation", "relation"),
sector = c("construction", "investment banking", "retail",
"pharmaceuticals", "trading company", "shipping"), `was founder` = c("True",
"True", "True", "True", "True", "True"), `was political` = c("False",
"False", "False", "False", "False", "True"), wealth.type = c("self-made finance",
"inherited", "inherited", "inherited", "inherited", "inherited"
), worth_billions = c(1, 2.5, 1.2, 1, 2.2, 1), year = c(1996L,
1996L, 1996L, 1996L, 1996L, 1996L)), row.names = c(NA, -6L
), spec = structure(list(cols = list(age = structure(list(), class = c("collector_integer",
"collector")), category = structure(list(), class = c("collector_character",
"collector")), citizenship = structure(list(), class = c("collector_character",
"collector")), company.name = structure(list(), class = c("collector_character",
"collector")), company.type = structure(list(), class = c("collector_character",
"collector")), `country code` = structure(list(), class = c("collector_character",
"collector")), founded = structure(list(), class = c("collector_integer",
"collector")), `from emerging` = structure(list(), class = c("collector_character",
"collector")), gdp = structure(list(), class = c("collector_double",
"collector")), gender = structure(list(), class = c("collector_character",
"collector")), industry = structure(list(), class = c("collector_character",
"collector")), inherited = structure(list(), class = c("collector_character",
"collector")), name = structure(list(), class = c("collector_character",
"collector")), rank = structure(list(), class = c("collector_integer",
"collector")), region = structure(list(), class = c("collector_character",
"collector")), relationship = structure(list(), class = c("collector_character",
"collector")), sector = structure(list(), class = c("collector_character",
"collector")), `was founder` = structure(list(), class = c("collector_character",
"collector")), `was political` = structure(list(), class = c("collector_character",
"collector")), wealth.type = structure(list(), class = c("collector_character",
"collector")), `worth in billions` = structure(list(), class = c("collector_double",
"collector")), year = structure(list(), class = c("collector_integer",
"collector"))), default = structure(list(), class = c("collector_guess",
"collector"))), class = "col_spec"), class = c("tbl_df", "tbl",
"data.frame"))
load("bil.RData")
print(bil)
# Renaming a few columns for spacing issues
colnames(bil)[21] <- "worth_billions"
colnames(bil)[6] <- "country_code"
# Finding where billionaires are oldest/youngest on average,
# ... then removing less than five observations
bil %>%
filter(!is.na(age)) %>%
select(age, worth_billions, country_code) %>%
group_by(age, worth_billions, country_code) %>%
mutate(count = n()) %>%
arrange(country_code) %>%
#spread(key = country_code, value = "USA") %>%
print()
I expect to find the country that has the oldest billionaires and youngest billionaires, excluding countries with fewer than five observations. Any help is appreciated!

Answer 1

After removing the NA elements in 'age' (filter), grouped by 'country_code' and filter out the groups having less than 5 billionaires, then summarise the mean of 'age' and slice the row having the maximum value for 'ageMean'
library(dplyr)
bil %>%
filter(!is.na(age)) %>%
group_by(country_code) %>%
filter(sum(worth_billions) > 1.0) > 5) %>%
summarise(ageMean = mean(age)) %>%
slice(which.max(ageMean))