Age groups into monthly buckets - r

Question

I'm struggling to find a solution for the following problem. I have a df with id's/ dob's and another monthbucket df as following
set.seed(33)
df <- data.frame(dob = sample(seq(as.Date('1940/01/01'), as.Date('2010/01/01'), by="day"), 10),
id = seq(1:10) )
monthbucket <- data.frame(month = format(seq(as.Date("2010-01-01"),as.Date("2011-01-01"),by="months"),'%Y-%m'),
startmonth = seq(as.Date("2010-01-01"),as.Date("2011-01-01"),by="months"),
endmonth = seq(as.Date("2010-02-01"),as.Date("2011-02-01"),by="months")-1)
I want to get an output which gives me the count of members within age groups (<19, 19-64, >64) for each of my monthly buckets. The count obviously switches over the year when people have birthdays.
I got the age calculation with something like:
age.fct <- function(dob, bucketdate) {
period <- as.period(interval(dob, bucketdate),unit = "year")
period$year}
I guess the general approach would be to calculate the age for each monthbucket, assign into one of the 3 age groups and count it up by month. Any suggestions?
EDIT 1.
Thanks for all the different approaches, I just run a brief benchmark on the solutions to determine which answer to accept. Somehow the data table solution didn't work on my test data set but I will check as soon as I have a few minutes in the next days.
set.seed(33)
df <- data.frame(dob = sample(seq(as.Date('1940/01/01'), as.Date('2010/01/01'), by="day"), 10000),
id = seq(1:10000) )
monthbucket <- data.frame(month = format(seq(as.Date("2010-01-01"),as.Date("2011-01-01"),by="months"),'%Y-%m'),
startmonth = seq(as.Date("2010-01-01"),as.Date("2011-01-01"),by="months"),
endmonth = seq(as.Date("2010-02-01"),as.Date("2011-02-01"),by="months")-1)
birth_days <- df$dob
month_bucket <- monthbucket$startmonth
and the benchmark
microbenchmark::microbenchmark(
MM= monthbucket %>% group_by_all %>% expand(id=df$id) %>% left_join(.,{df %>% mutate(birth_month =cut(dob, "month"))},by="id") %>% mutate(age=time_length(difftime(startmonth, birth_month),"years")) %>%
mutate(age_cat=case_when(age<19 ~ "<19", age>64 ~ ">64",TRUE ~ "19-64")) %>% group_by(month) %>% count(age_cat) %>% gather(variable, count, n) %>%
unite(variable, age_cat) %>% spread(variable, count)
,
AkselA = {ages <- as.data.frame(t(unclass(outer(monthbucket$startmonth, df$dob, "-")/365.25)))
ages <- do.call(data.frame, lapply(ages, cut, c(0, 19, 64, Inf), c("0-19", "19-64", "64+")))
ages <- sapply(ages, table)
colnames(ages) <- monthbucket$month
},
Cole1 ={t(table(apply(X = outer(month_bucket, birth_days, `-`) / 365.25, MARGIN = 2, FUN = cut, c(0,19,65, Inf)), rep(format(month_bucket,'%Y-%m'), length(birth_days))))
},
# cole2={ cast(CJ(month_bucket, birth_days)[, .N, by = .(month_bucket , cut(as.numeric(month_bucket - birth_days)/365.25, c(0,19,65,Inf)))], month_bucket ~ cut, value.var = 'N')
# },
#
Cole3={crossing(month_bucket, birth_days)%>%count(month_bucket, age_range = cut(as.numeric(month_bucket - birth_days) / 365.25, c(0,19,65,Inf)))%>%spread(age_range, n)
},
Cole4={all_combos <- expand.grid(month_bucket = month_bucket, birth_days = birth_days)
all_combos$age <- as.numeric(all_combos$month_bucket - all_combos$birth_days) / 365.25
all_combos$cut_r <- cut(all_combos$age, c(0,19,65,Inf))
reshape(data = aggregate( all_combos$month_bucket, by = list(bucket = all_combos$month_bucket,age_group = all_combos$cut_r), FUN = length), timevar = 'age_group' , idvar = 'bucket', direction = 'wide' )
},
times = 1L)
Unit: milliseconds
expr min lq mean median uq max neval
MM 4249.02810 4249.02810 4249.02810 4249.02810 4249.02810 4249.02810 1
AkselA 17.12697 17.12697 17.12697 17.12697 17.12697 17.12697 1
Cole1 3237.94534 3237.94534 3237.94534 3237.94534 3237.94534 3237.94534 1
Cole3 23.63945 23.63945 23.63945 23.63945 23.63945 23.63945 1
Cole4 877.92782 877.92782 877.92782 877.92782 877.92782 877.92782 1
Based on speed AkselA's approach seems to be the fastest but I get a different result for M-M's approach compared to all others (once AkselA's changes to 65 in the cut part cut, c(0, 19, 64, Inf)... I will accept answer based on speed but will look into the differences in the results!

Answer 1

Not very sophisticated but I joined the two tables (first expanded monthbucket on df$id) and then calculated the age (as you have the whole month, I just calculated difftime with the first day of month of birth and startmonth). Then, for each month (bucket) I counted number of different age groups and at the end converted long format to wide for better illustration.
library(lubridate)
library(tidyverse)
monthbucket %>%
group_by_all %>%
expand(id=df$id) %>%
left_join(.,{df %>%
mutate(birth_month =cut(dob, "month"))},
by="id") %>%
mutate(age=time_length(difftime(startmonth, birth_month),"years")) %>%
mutate(age_cat=case_when(age<19 ~ "<19",
age>64 ~ ">64",
TRUE ~ "19-64")) %>%
group_by(month) %>%
count(age_cat) %>%
gather(variable, count, n) %>%
unite(variable, age_cat) %>%
spread(variable, count)
#> # A tibble: 13 x 4
#> # Groups: month [13]
#> month `<19` `>64` `19-64`
#> <fct> <int> <int> <int>
#> 1 2010-01 3 2 5
#> 2 2010-02 3 2 5
#> 3 2010-03 3 2 5
#> 4 2010-04 3 2 5
#> 5 2010-05 3 2 5
#> 6 2010-06 3 2 5
#> 7 2010-07 3 2 5
#> 8 2010-08 3 2 5
#> 9 2010-09 3 2 5
#> 10 2010-10 3 2 5
#> 11 2010-11 3 2 5
#> 12 2010-12 3 2 5
#> 13 2011-01 3 2 5
Created on 2019-07-03 by the reprex package (v0.3.0)

Answer 2

Assuming I understand your request.
ages <- as.data.frame(t(unclass(outer(monthbucket$startmonth, df$dob, "-")/365.25)))
ages <- do.call(data.frame,
lapply(ages, cut, c(0, 19, 64, Inf), c("0-19", "19-64", "64+")))
ages <- sapply(ages, table)
colnames(ages) <- monthbucket$month
ages
# 2010-01 2010-02 2010-03 2010-04 2010-05 2010-06 2010-07 2010-08 2010-09 2010-10 2010-11 2010-12 2011-01
# 0-19 2 2 2 2 2 2 2 2 2 2 2 2 2
# 19-64 7 7 7 7 7 7 7 7 7 7 7 7 7
# 64+ 1 1 1 1 1 1 1 1 1 1 1 1 1
#

Answer 3

There are some similarities to #AkselA's answer as it depends on outer(), cut(), and table().
set.seed(33)
birth_days <- sample(seq(as.Date('1940/01/01'), as.Date('2010/01/01'), by="day"), 10)
month_bucket <- seq(as.Date("2010-01-01"),as.Date("2011-01-01"),by="months")
t(
table(
apply(
X = outer(month_bucket, birth_days, `-`) / 365.25
, MARGIN = 2
, FUN = cut, c(0,19,65, Inf)
)
, rep(format(month_bucket,'%Y-%m'), length(birth_days))
)
)
(0,19] (19,65] (65,Inf]
2010-01 2 7 1
2010-02 2 7 1
2010-03 2 7 1
2010-04 2 7 1
2010-05 2 7 1
2010-06 2 7 1
2010-07 2 7 1
2010-08 2 7 1
2010-09 2 7 1
2010-10 2 7 1
2010-11 2 7 1
2010-12 2 7 1
2011-01 2 7 1
I felt weird having such a similar solution so here is data.table:
library(data.table)
dcast(
CJ(month_bucket, birth_days
)[, .N
, by = .(month_bucket
, cut(as.numeric(month_bucket - birth_days)/365.25, c(0,19,65,Inf)))
]
, month_bucket ~ cut
, value.var = 'N')
dplyr and tidyr:
library(dplyr)
library(tidyr)
crossing(month_bucket, birth_days)%>%
count(month_bucket
, age_range = cut(as.numeric(month_bucket - birth_days) / 365.25, c(0,19,65,Inf))
)%>%
spread(age_range, n)
And a similar approach in base that I'm not completely happy with.
all_combos <- expand.grid(month_bucket = month_bucket, birth_days = birth_days)
all_combos$age <- as.numeric(all_combos$month_bucket - all_combos$birth_days) / 365.25
all_combos$cut_r <- cut(all_combos$age, c(0,19,65,Inf))
reshape(
data = aggregate(
all_combos$month_bucket
, by = list(bucket = all_combos$month_bucket
,age_group = all_combos$cut_r)
, FUN = length)
, timevar = 'age_group'
, idvar = 'bucket'
, direction = 'wide'
)